This adds documentation to several features of the LSP. Specifically:

Functions, methods, classes, class constants and class properties will now display their documentation/description in the IDE's Hover information, Autocomplete lists and Signature Information.

Here's some examples:

Autocomplete documentation:

Hover documentation:

Documentation in function param signature

I mostly modeled these off the default TypeScript documentation in VS Code.

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This is blocked on felixfbecker/php-language-server-protocol#17

Personally I am bullish on including documentation on all the PHP inbuilt functions, this reflects what the Typescript / JS LSP by default also does.

I didn't yet add guards around all documentation collection for the LSP only -- I wasn't quite sure how to do that (I imagine that is stored in the config object?), though I wasn't sure how difficult it would be to get the scope/context of that value at each point.

As a comparison, I ran ./vendor/bin/psalm --no-cache --no-reflection-cache --no-file-cache . on a pretty large WordPress project (which makes a lot of use of phpdocumentation)

master
Checks took 5.19 seconds and used 552.723MB of memory

lsp-documentation
Checks took 5.19 seconds and used 554.804MB of memory