…, r=notriddle

Rewrite error index generator to greatly reduce the size of the pages

Fixes rust-lang#100736.

Instead of having all error codes in a same page (making the DOM way too big), I split the output into multiple files and generated a list of links (if there is an explanation) to the error codes' explanation into the already existing file.

I also used this opportunity to greatly simplify the code. Instead of needing a `build.rs`, I simply imported the file we want and wrote the macro which generates a function containing everything we need. We just need to call it to get the error codes and their explanation (if any). Also, considering the implementations between markdown and HTML formats differed even further, the `Formatter` trait was becoming too problematic so I removed it too.

You can test it [here](https://rustdoc.crud.net/imperio/rewrite-error-index/error-index.html).

cc `@jsha`
r? `@notriddle`

…iaskrgr

Rollup of 15 pull requests

Successful merges:

 - rust-lang#99993 (linker: Update some outdated comments)
 - rust-lang#100220 (Properly forward `ByRefSized::fold` to the inner iterator)
 - rust-lang#100826 (sugg: take into count the debug formatting)
 - rust-lang#100855 (Extra documentation for new formatting feature)
 - rust-lang#100888 (Coherence negative impls implied bounds)
 - rust-lang#100901 (Make some methods private)
 - rust-lang#100906 (Suggest alternatives when trying to mutate a `HashMap`/`BTreeMap` via indexing)
 - rust-lang#100912 (Diagnose missing includes in run-make tests)
 - rust-lang#100919 (Use par_body_owners for liveness)
 - rust-lang#100922 (Rewrite error index generator to greatly reduce the size of the pages)
 - rust-lang#100926 (Update README.md)
 - rust-lang#100930 (Use `--userns=keep-id` when "docker" is really podman)
 - rust-lang#100938 (rustdoc: remove unused CSS rule)
 - rust-lang#100940 (Do not suggest adding a bound to a opaque type)
 - rust-lang#100945 (Add a missing test case for impl generic mismatch)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

… r=notriddle

Generate error index with mdbook instead of raw HTML pages

This is a follow-up of rust-lang#100922.

This comes from a remark from `@estebank` who said that the search was a nice thing on the previous version and that it wasn't possible anymore. An easy way to come around this limitation was to use `mdbook`, which is what I did here.

Now some explanations on the code. I'll explain how I developed this and why I reached this solution. First I did it very basically by simply setting the source directory and the output directory, generated a `SUMMARY.md` manually which listed all error codes and that was it. Two problems arose from this:
 1. A lot of new HTML files were generated at the top level
 2. An `index.html` file was generated at the top-level (the summary in short).

So for `1.`, it's not great to have too many files at the top-level as it could create file conflicts more easily. And for `2.`, this is actually a huge issue because <doc.rust-lang.org> generates an `index.html` file with a links to a few different resources, so it should never be overwritten. <s>Unfortunately, `mdbook` **always** generates an `index.html` file so the only solution I could see (except for sending them a contribution, I'll maybe do that later) was to temporaly move a potentially existing `index.html` file and then puts it back once done. For this last part, to ensure that we don't return *before* it has been put back, I wrapped the `mdbook` generation code inside `render_html_inner` which is called from `render_html` which in turn handle the "save" of `index.html`.</s>

EDIT: `mdbook` completely deletes ALL the content in the target directory so I instead generate into a sub directory and then I move the files to the real target directory.

To keep compatibility with the old version, I also put the `<script>` `@notriddle` nicely provided in the previous PR only into the `error-index.html` file to prevent unneeded repetition. I didn't use `mdbook` `additional-js` option because the JS is included at the end of all HTML files, which we don't want for two reasons:
 1. It's slow.
 2. We only want it to be run in `error-index.html` (even if we also ensure in the JS itself too!).

<s>Now the last part: why we generate the summary twice. We actually generate it once to tell `mdbook` what the book will look like and a second time because a create a new chapter content which will actually list all the error codes (with the updated paths).</s>

EDIT: I removed the need for two summaries.

You can test it [here](https://rustdoc.crud.net/imperio/error-index-mdbook/error-index.html).

r? `@notriddle`

… r=notriddle

Generate error index with mdbook instead of raw HTML pages

This is a follow-up of rust-lang#100922.

This comes from a remark from ``@estebank`` who said that the search was a nice thing on the previous version and that it wasn't possible anymore. An easy way to come around this limitation was to use `mdbook`, which is what I did here.

Now some explanations on the code. I'll explain how I developed this and why I reached this solution. First I did it very basically by simply setting the source directory and the output directory, generated a `SUMMARY.md` manually which listed all error codes and that was it. Two problems arose from this:
 1. A lot of new HTML files were generated at the top level
 2. An `index.html` file was generated at the top-level (the summary in short).

So for `1.`, it's not great to have too many files at the top-level as it could create file conflicts more easily. And for `2.`, this is actually a huge issue because <doc.rust-lang.org> generates an `index.html` file with a links to a few different resources, so it should never be overwritten. <s>Unfortunately, `mdbook` **always** generates an `index.html` file so the only solution I could see (except for sending them a contribution, I'll maybe do that later) was to temporaly move a potentially existing `index.html` file and then puts it back once done. For this last part, to ensure that we don't return *before* it has been put back, I wrapped the `mdbook` generation code inside `render_html_inner` which is called from `render_html` which in turn handle the "save" of `index.html`.</s>

EDIT: `mdbook` completely deletes ALL the content in the target directory so I instead generate into a sub directory and then I move the files to the real target directory.

To keep compatibility with the old version, I also put the `<script>` ``@notriddle`` nicely provided in the previous PR only into the `error-index.html` file to prevent unneeded repetition. I didn't use `mdbook` `additional-js` option because the JS is included at the end of all HTML files, which we don't want for two reasons:
 1. It's slow.
 2. We only want it to be run in `error-index.html` (even if we also ensure in the JS itself too!).

<s>Now the last part: why we generate the summary twice. We actually generate it once to tell `mdbook` what the book will look like and a second time because a create a new chapter content which will actually list all the error codes (with the updated paths).</s>

EDIT: I removed the need for two summaries.

You can test it [here](https://rustdoc.crud.net/imperio/error-index-mdbook/error-index.html).

r? ``@notriddle``

… r=notriddle

Generate error index with mdbook instead of raw HTML pages

This is a follow-up of rust-lang#100922.

This comes from a remark from ```@estebank``` who said that the search was a nice thing on the previous version and that it wasn't possible anymore. An easy way to come around this limitation was to use `mdbook`, which is what I did here.

Now some explanations on the code. I'll explain how I developed this and why I reached this solution. First I did it very basically by simply setting the source directory and the output directory, generated a `SUMMARY.md` manually which listed all error codes and that was it. Two problems arose from this:
 1. A lot of new HTML files were generated at the top level
 2. An `index.html` file was generated at the top-level (the summary in short).

So for `1.`, it's not great to have too many files at the top-level as it could create file conflicts more easily. And for `2.`, this is actually a huge issue because <doc.rust-lang.org> generates an `index.html` file with a links to a few different resources, so it should never be overwritten. <s>Unfortunately, `mdbook` **always** generates an `index.html` file so the only solution I could see (except for sending them a contribution, I'll maybe do that later) was to temporaly move a potentially existing `index.html` file and then puts it back once done. For this last part, to ensure that we don't return *before* it has been put back, I wrapped the `mdbook` generation code inside `render_html_inner` which is called from `render_html` which in turn handle the "save" of `index.html`.</s>

EDIT: `mdbook` completely deletes ALL the content in the target directory so I instead generate into a sub directory and then I move the files to the real target directory.

To keep compatibility with the old version, I also put the `<script>` ```@notriddle``` nicely provided in the previous PR only into the `error-index.html` file to prevent unneeded repetition. I didn't use `mdbook` `additional-js` option because the JS is included at the end of all HTML files, which we don't want for two reasons:
 1. It's slow.
 2. We only want it to be run in `error-index.html` (even if we also ensure in the JS itself too!).

<s>Now the last part: why we generate the summary twice. We actually generate it once to tell `mdbook` what the book will look like and a second time because a create a new chapter content which will actually list all the error codes (with the updated paths).</s>

EDIT: I removed the need for two summaries.

You can test it [here](https://rustdoc.crud.net/imperio/error-index-mdbook/error-index.html).

r? ```@notriddle```

… r=notriddle

Generate error index with mdbook instead of raw HTML pages

This is a follow-up of rust-lang#100922.

This comes from a remark from ```@estebank``` who said that the search was a nice thing on the previous version and that it wasn't possible anymore. An easy way to come around this limitation was to use `mdbook`, which is what I did here.

Now some explanations on the code. I'll explain how I developed this and why I reached this solution. First I did it very basically by simply setting the source directory and the output directory, generated a `SUMMARY.md` manually which listed all error codes and that was it. Two problems arose from this:
 1. A lot of new HTML files were generated at the top level
 2. An `index.html` file was generated at the top-level (the summary in short).

So for `1.`, it's not great to have too many files at the top-level as it could create file conflicts more easily. And for `2.`, this is actually a huge issue because <doc.rust-lang.org> generates an `index.html` file with a links to a few different resources, so it should never be overwritten. <s>Unfortunately, `mdbook` **always** generates an `index.html` file so the only solution I could see (except for sending them a contribution, I'll maybe do that later) was to temporaly move a potentially existing `index.html` file and then puts it back once done. For this last part, to ensure that we don't return *before* it has been put back, I wrapped the `mdbook` generation code inside `render_html_inner` which is called from `render_html` which in turn handle the "save" of `index.html`.</s>

EDIT: `mdbook` completely deletes ALL the content in the target directory so I instead generate into a sub directory and then I move the files to the real target directory.

To keep compatibility with the old version, I also put the `<script>` ```@notriddle``` nicely provided in the previous PR only into the `error-index.html` file to prevent unneeded repetition. I didn't use `mdbook` `additional-js` option because the JS is included at the end of all HTML files, which we don't want for two reasons:
 1. It's slow.
 2. We only want it to be run in `error-index.html` (even if we also ensure in the JS itself too!).

<s>Now the last part: why we generate the summary twice. We actually generate it once to tell `mdbook` what the book will look like and a second time because a create a new chapter content which will actually list all the error codes (with the updated paths).</s>

EDIT: I removed the need for two summaries.

You can test it [here](https://rustdoc.crud.net/imperio/error-index-mdbook/error-index.html).

r? ```@notriddle```

… r=notriddle

Generate error index with mdbook instead of raw HTML pages

This is a follow-up of rust-lang#100922.

This comes from a remark from ````@estebank```` who said that the search was a nice thing on the previous version and that it wasn't possible anymore. An easy way to come around this limitation was to use `mdbook`, which is what I did here.

Now some explanations on the code. I'll explain how I developed this and why I reached this solution. First I did it very basically by simply setting the source directory and the output directory, generated a `SUMMARY.md` manually which listed all error codes and that was it. Two problems arose from this:
 1. A lot of new HTML files were generated at the top level
 2. An `index.html` file was generated at the top-level (the summary in short).

So for `1.`, it's not great to have too many files at the top-level as it could create file conflicts more easily. And for `2.`, this is actually a huge issue because <doc.rust-lang.org> generates an `index.html` file with a links to a few different resources, so it should never be overwritten. <s>Unfortunately, `mdbook` **always** generates an `index.html` file so the only solution I could see (except for sending them a contribution, I'll maybe do that later) was to temporaly move a potentially existing `index.html` file and then puts it back once done. For this last part, to ensure that we don't return *before* it has been put back, I wrapped the `mdbook` generation code inside `render_html_inner` which is called from `render_html` which in turn handle the "save" of `index.html`.</s>

EDIT: `mdbook` completely deletes ALL the content in the target directory so I instead generate into a sub directory and then I move the files to the real target directory.

To keep compatibility with the old version, I also put the `<script>` ````@notriddle```` nicely provided in the previous PR only into the `error-index.html` file to prevent unneeded repetition. I didn't use `mdbook` `additional-js` option because the JS is included at the end of all HTML files, which we don't want for two reasons:
 1. It's slow.
 2. We only want it to be run in `error-index.html` (even if we also ensure in the JS itself too!).

<s>Now the last part: why we generate the summary twice. We actually generate it once to tell `mdbook` what the book will look like and a second time because a create a new chapter content which will actually list all the error codes (with the updated paths).</s>

EDIT: I removed the need for two summaries.

You can test it [here](https://rustdoc.crud.net/imperio/error-index-mdbook/error-index.html).

r? ````@notriddle````