Rollup merge of #88277 - ehuss:update-books, r=ehuss

Update books

## reference

1 commits in 4884fe45c14f8b22121760fb117181bb4da8dfe0..da6ea9b03f74cae0a292f40315723d7a3a973637
2021-07-28 21:31:28 -0700 to 2021-08-19 21:28:10 -0700
- Allow users to change status labels (rust-lang/reference#1083)

## book

7 commits in 7e49659102f0977d9142190e1ba23345c0f00eb1..687e21bde2ea10c261f79fa14797c5137425098d
2021-08-03 21:41:35 -0400 to 2021-08-18 20:48:38 -0400
- Small tweaks to Ferris size and position
- Retain previous height: auto just in case
- Shrink and move ferris when possible
- Snapshot chapter 6 for nostarch
- Demonstrate variable as catch-all for match. Fixes rust-lang/book#1868.
- Improve the if let example to have a binding pattern. Fixes rust-lang/book#1401.
- Fixes typo (rust-lang/book#2816)

## rust-by-example

1 commits in 0dc9cd4e89f00cb5230f120e1a083916386e422b..04f489c889235fe3b6dfe678ae5410d07deda958
2021-07-23 09:14:27 -0300 to 2021-08-17 08:01:20 -0300
- Grammar mistake (rust-lang/rust-by-example#1456)

## rustc-dev-guide

5 commits in c4644b427cbdaafc7a87be0ccdf5d8aaa07ac35f..cf0e151b7925a40f13fbc6573c6f97d5f94c7c17
2021-08-10 20:41:44 +0900 to 2021-08-22 11:47:02 -0300
- Fix typo “a Rc” → “an Rc” (rust-lang/rustc-dev-guide#1191)
- Expand THIR section with more details (rust-lang/rustc-dev-guide#1183)
- Remove docs for old -Z profile-queries flag
- update mdbook version to latest
- allow to quickly edit a page directly on github