Include nonexported macro_rules! macros in the doctest target

Fixes rust-lang#88038

This PR aims to include nonexported `macro_rules!` macros in the doctest target. For more details, please see the above issue.

935: Convert delegate doctest to unit tests r=cuviper a=cuviper

The documented example wasn't functional, and this broke on nightly since rust-lang/rust#96630.

We can't actually doctest a nonexported macro, but a unit test will do.

Co-authored-by: Josh Stone <cuviper@gmail.com>

Nightly has begun running doctests for unexported macros as of
rust-lang/rust#96630, which caused a doctest for
test_unpack_octets_4 which was previously ignored to be run. This broke
the CI because macros that are not exported with `#[macro_export]`
cannot be used from external crates (and thus cannot be doctested). This
change ignores the doctest and copies the relevant code into a unit
test.

Nightly has begun running doctests for unexported macros as of
rust-lang/rust#96630, which caused a doctest for
test_unpack_octets_4 which was previously ignored to be run. This broke
the CI because macros that are not exported with `#[macro_export]`
cannot be used from external crates (and thus cannot be doctested). This
change ignores the doctest and copies the relevant code into a unit
test.

Co-authored-by: David Koloski <dkoloski@google.com>

1730: Ignore doctests for unexported macros r=asomers a=zombiepigdragon

Due to rust-lang/rust#97030, cargo test will fail to doctest macros unless they are exported, breaking the examples for `libc_bitflags!` and `libc_enum!`.

Adds `ignore` to the examples for these macros to stop tests from failing.

`cargo test` already fails on cargo 1.62.0-beta.2, and the above issue makes it seem unlikely that this will be changed on the Rust side. If rust-lang/rust#96630 *does* get reverted, this PR can be closed/unmerged, although the test wasn't running beforehand, and it might be worth making this explicit regardless.

Co-authored-by: Alex Rawson <ajzecrom@gmail.com>

Since Rust 1.62.0, doctests on macros are run even if the macro isn't
marked #[macro_export] [0]. Because the macro can't actually be accessed
externally, we explicitly mark the doctest as ignored so it continues
not to be run.

[0]: rust-lang/rust#96630

Since Rust 1.62.0, doctests on macros are run even if the macro isn't
marked #[macro_export] [0]. Because the macro can't actually be accessed
externally, we explicitly mark the doctest as ignored so it continues
not to be run.

[0]: rust-lang/rust#96630

Add macro_rules! rustdoc change to 1.62 relnotes

rust-lang#96630 was tagged <kbd>relnotes</kbd> but didn't make it into the notes. Given this is a compatibility issue (rust-lang#97030, rust-lang#98735, rust-lang#98743), it probably *should* be retroactively added.