There only needs to be one `Fn` per symbol, not multiple.

Some are too long (> 100 chars), some are too short, some are missing
full stops, some are missing upper-case letters at the start of
sentences.

In several files they are entirely unnecessary, with the relevant names
already imported. And in a few I have added the necessary `use` item.

…=workingjubilee

Implement `normalize_lexically`

Implements rust-lang#134694

This is, I think, the most straightforward implementation I could do, which will hopefully more easily allow experimentation if we decide to change the design here.

…ups, r=jdonszelmann

Simplify `attribute_groups`

It's more complicated than it needs to be.

r? ``@jdonszelmann``

…der, r=lolbinarycat

[rustdoc] Unify type aliases rendering with other ADT

Fixes rust-lang#140739.

Better reviewed one commit at a time.

Just one thing I'm wondering: should we also render non-`repr` attributes? If so, I wonder if we shouldn't simply change `clean::TypeAlias` to contain the other ADT directly (`Struct`, `Enum` and `Union`) and remove the `TypeAlias::generics` field.

Can be done in a follow-up too.

cc ``@camelid``
r? ``@notriddle``

…kingjubilee

Clarify WTF-8 safety docs

This PR is a follow-up to PR rust-lang#140159, which clarifies ~~two things~~:
- the WTF-8 safety comment [was confusing](rust-lang#140159 (comment)), either surrogate condition is actually sufficient for safety, both are not required
- ~~the private `os_str::Slice` type name is easily confused with `std::slice`~~

~~Happy to bikeshed the `OsSlice` name, other alternatives are `OsStrSlice` and `StrSlice`. Now it's got a distinct name from `std::slice`, it's easy to search and replace.~~

cc ``@thaliaarchi`` ``@workingjubilee``

…tion, r=dtolnay

Specify that split_ascii_whitespace uses the same definition as is_ascii_whitespace

Attempt to improve the `std::fs::create_dir_all` docs related to atomicity

The original paragraph was added in rust-lang#124520. It doesn't match the actual code logic. It says "function returns an error" if "the parent components" _(which also implies directories)_ "have been created already". The code is as follows:

https://github.com/rust-lang/rust/blob/e88e85463468ce5d5ce468414eb69e3b15fa8d42/library/std/src/fs.rs#L3146
https://github.com/rust-lang/rust/blob/e88e85463468ce5d5ce468414eb69e3b15fa8d42/library/std/src/fs.rs#L3160

These lines suppress all errors if any path component is a directory. I've updated the paragraph to mirror this.

…ld, r=Kobzol

ci: move PR job x86_64-gnu-tools to codebuild

…_unstable, r=compiler-errors

const-check: stop recommending the use of rustc_allow_const_fn_unstable

I have seen way too many people see the compiler suggest this attribute and then just apply it without a second thought. This is bad. So let's just stop recommending it; for the rare case where someone needs it, they'll eventually ask us and that way we can be sure that it is truly needed. The dev-guide still also explains `rustc_allow_const_fn_unstable`.

Cc ``@rust-lang/wg-const-eval``