There is no `as_str` function on Ident any more.

Also change it to an intra doc link while we're at it.

This is mostly motivated by docs.rs. It's really weird
when arrow keys work in the top dropdown menu, but don't work
in other dropdown menus on the same page.

Most of the code in mod.rs should be code that really needs to have
the list of available themes inlined into it.

The comment has become outdated as the array_impl macro
has been removed.

filter_next
manual_strip
redundant_static_lifetimes
single_char_pattern
unnecessary_cast
unused_unit
op_ref
redundant_closure
useless_conversion

This was recommended by GitHub Support to try reducing the things that
could've caused rust-lang#78743. I checked the changelog and there should be no
practical impact for us (we already set an explicit fetch-depth).

`crate::` -> `core::`

It looks weird to have `crate::` in the link text and we use the actual
crate name everywhere else.

If anyone is curious, I used this Vim command to update all the links:

    %s/\(\s\)\[`crate::\(.*\)`\]/\1[`core::\2`](crate::\2)/g

'Note however,' -> 'Note, however,'

paramter -> parameter

…=jyn514

Move Vec UI tests to unit tests when possible

Helps with rust-lang#76268.

I'm moving the tests using `Vec` or `VecDeque`.

`@rustbot` modify labels: A-testsuite C-cleanup T-libs

Make it more clear what an about async fn's returns when referring to what it returns

see rust-lang#76547

This is *likely* not the ONLY place that this happens to be unclear, but we can move this fn to rustc_middle or something like that and reuse it if need be, to apply it to more diagnostics

One outstanding question I have is, if the fn returns (), should I make the message more clear (what about `fn f()` vs `fn f() -> ()`, can you tell those apart in the hir?)

R? `@tmandry`

`@rustbot` modify labels +A-diagnostics +T-compiler

Clean up docs for 'as' keyword

Change as_str → to_string in proc_macro::Ident::span() docs

There is no `as_str` function on Ident any more.

Also change it to an intra doc link while we're at it.

Add keyboard handling to the theme picker menu

This PR is mostly designed to bring the theme picker closer to feature parity with the menu bar from docs.rs. Though the rustdoc theme picker is technically already usable from the keyboard, it's really weird that arrow keys work on some of the menus, but not all of them, in the exact same page.

Array trait impl comment/doc fixes

Two small doc/comment fixes regarding trait implementations on arrays.

…eGomez

(rustdoc) fix test for trait impl display

The test checks that parameters and return values with `impl Trait` types are correctly generated in rustdoc's output.

In essence, the previous version of the test checked the absence of values that would never be generated by rustdoc, so it could basically never fail. These values were adjusted to the expected output and are now required to exist in rustdoc's output. See rust-lang#55201 (comment) for a detailed explanation of the reasoning behind the changes.

Note that the output of rustdoc for `impl Trait`s in parameters and return values did not change since the inital test creation, so this PR only modifies the test.

Closes rust-lang#55201

fix a couple of clippy warnings:

filter_next
manual_strip
redundant_static_lifetimes
single_char_pattern
unnecessary_cast
unused_unit
op_ref
redundant_closure
useless_conversion

…cell-getmut, r=RalfJung

Simplify the implementation of `get_mut` (no unsafe)

Quick PR to reduce one use of `unsafe` pointed out in the previous PR

r? `@RalfJung`

…brary-core, r=jyn514

Move range in ui test to ops test in library/core

Helps with rust-lang#76268

r? `@matklad`

…mulacrum

Bump actions/checkout to version 2

This was recommended by GitHub Support to try reducing the things that could've caused rust-lang#78743. I checked the changelog and there should be no practical impact for us (we already set an explicit fetch-depth).

r? `@Mark-Simulacrum`

Improve and clean up some intra-doc links

Fixed typo in comment

paramter -> parameter