This is in preparation to upgrade to 8.0.1, so the next commit
can contain more meaningful diffs.

From https://github.com/necolas/normalize.css/releases/tag/8.0.1.

This bypasses tidy's complaints about tab indent. Also, this lets us
remove comments while keeping the MIT license comment.

See rust-lang#82379 (comment)

WASI's `filestat` type includes a size field, so expose it in
`MetadataExt` via a `size()` function, similar to the corresponding Unix
function.

These ensure that these tests pass regardless of what RUST_BACKTRACE is
set to in the user's shell.

This adds API documentation support for `std::os::wasi` modeled after
how `std::os::unix` works, so that WASI can be documented [here] along
with the other platforms.

[here]: https://doc.rust-lang.org/stable/std/os/index.html

Two changes of particular interest:

 - This changes the `AsRawFd` for `io::Stdin` for WASI to return
   `libc::STDIN_FILENO` instead of `sys::stdio::Stdin.as_raw_fd()` (and
   similar for `Stdout` and `Stderr`), which matches how the `unix`
   version works. `STDIN_FILENO` etc. may not always be explicitly
   reserved at the WASI level, but as long as we have Rust's `std` and
   `libc`, I think it's reasonable to guarantee that we'll always use
   `libc::STDIN_FILENO` for stdin.

 - This duplicates the `osstr2str` utility function, rather than
   trying to share it across all the configurations that need it.

It makes it clearer that the `Namespace` is the one requested by the
disambiguator, rather than the actual namespace of the item. It said
that in the docs before, but now you can tell in the code so it reduces
the potential for confusion.

- Currently style triggers rust-lang#81183 so we can't add `#[instrument]` to
  this function.

- Having docs above the header is more consistent with the rest of the
  code base.

Use #[doc = include_str!()] in std

cc rust-lang#78835 (comment)
r? ```@jyn514```

…nup, r=jyn514

rustdoc: Name fields of `ResolutionFailure::WrongNamespace`

It makes it clearer that the `Namespace` is the one requested by the
disambiguator, rather than the actual namespace of the item. It said
that in the docs before, but now you can tell in the code so it reduces
the potential for confusion.

…pastorino

Cleanup `PpMode` and friends

This PR:
 - Separates `PpSourceMode` and `PpHirMode` to remove invalid states
 - Renames the variant to remove the redundant `Ppm` prefix
 - Adds basic documentation for the different pretty-print modes
 - Cleanups some code to make it more idiomatic

Not sure if this is actually useful, but it looks cleaner to me.

…umeGomez

Update normalize.css to 8.0.1

From From https://github.com/necolas/normalize.css/releases/tag/8.0.1.

The old version was 3.0.0, from 2014. The new version is from 2018.

I noticed when looking at frontend performance for rustdoc that this file was out of date. The URL in the 3.0.0 license header now resolves to an incorrect destination. And generally it seems good to be up-to-date.

Before-and-after images, plus diff, under details. TL;DR: Nothing changes except a slight adjustment to line height.

<details>

![with-normalize-8 0 1](https://user-images.githubusercontent.com/220205/108581849-bd5c8800-72e4-11eb-9150-78c8d67ca37a.png)

![with-normalize-3 0 0](https://user-images.githubusercontent.com/220205/108581848-bcc3f180-72e4-11eb-8b45-0cd1415a51e5.png)

![diff](https://user-images.githubusercontent.com/220205/108581890-dfeea100-72e4-11eb-93c5-6284492f54a9.png)

</details>

…mps, r=petrochenkov

Test hexagon-enum only when llvm target is present

See rust-lang#82379 (comment)

r? ```@petrochenkov```

```@bors``` rollup

Enable API documentation for `std::os::wasi`.

This adds API documentation support for `std::os::wasi` modeled after
how `std::os::unix` works, so that WASI can be documented [here] along
with the other platforms.

[here]: https://doc.rust-lang.org/stable/std/os/index.html

Two changes of particular interest:

 - This changes the `AsRawFd` for `io::Stdin` for WASI to return
   `libc::STDIN_FILENO` instead of `sys::stdio::Stdin.as_raw_fd()` (and
   similar for `Stdout` and `Stderr`), which matches how the `unix`
   version works. `STDIN_FILENO` etc. may not always be explicitly
   reserved at the WASI level, but as long as we have Rust's `std` and
   `libc`, I think it's reasonable to guarantee that we'll always use
   `libc::STDIN_FILENO` for stdin.

 - This duplicates the `osstr2str` utility function, rather than
   trying to share it across all the configurations that need it.

r? ```@alexcrichton```

…lexcrichton

Add a `size()` function to WASI's `MetadataExt`.

WASI's `filestat` type includes a size field, so expose it in
`MetadataExt` via a `size()` function, similar to the corresponding Unix
function.

r? ```@alexcrichton```

Set RUST_BACKTRACE=0 when running `treat-err-as-bug` tests

These ensure that these tests pass regardless of what RUST_BACKTRACE is
set to in the user's shell.

…Gomez

Fix typo in sanitizer flag in unstable book.

panic_bounds_checks should be panic_bounds_check

Update outdated comment in unix Command.

The big comment in the `Command` struct has been incorrect for some time (at least since rust-lang#46789 which removed `envp`). Rather than try to remove the allocations, this PR just updates the comment to reflect reality. There is an explanation for the reasoning at rust-lang#31409 (comment), discussing the potential of being able to call `Command::exec` after `libc::fork`.  That can still be done in the future, but I think for now it would be good to just correct the comment.

…etrochenkov

Move pick_by_value_method docs above function header

- Currently style triggers rust-lang#81183 so we can't add `#[instrument]` to
  this function.

- Having docs above the header is more consistent with the rest of the
  code base.