Rollup merge of #149894 - ehuss:mdbook-0.5, r=Mark-Simulacrum

Update to mdbook 0.5

This updates to mdbook 0.5.2 from mdbook 0.4.52. A primary aspect of this change is that it splits the `mdbook` crate into multiple crates, and various API changes and cleanup.

There's full release notes and a migration guide at https://github.com/rust-lang/mdBook/blob/master/CHANGELOG.md#mdbook-050.

This also includes submodule updates:

## book

1 commits in 8c0eacd5c4acbb650497454f3a58c9e8083202a4..9c9104e8a82430f97f42e738051bda718919211c
2025-11-18 10:36:41 -0500 to 2025-12-10 11:33:49 -0500
- Update to mdbook 0.5

## edition-guide

1 commits in 9cf5443d632673c4d41edad5e8ed8be86eeb3b8f..c3c0f0b3da26610138b7ba7663f60cd2c68cf184
2025-11-15 21:51:11 +0000 to 2025-11-28 18:54:18 +0000
- Update to mdbook 0.5 (rust-lang/edition-guide#381)

## nomicon

2 commits in 0fe83ab28985b99aba36a1f0dbde3e08286fefda..9fe8fa599ad228dda74f240cc32b54bc5c1aa3e6
2025-11-15 00:03:14 +0000 to 2025-12-03 11:54:04 +0000
- Remove references to outdated unsafe code guidelines (rust-lang/nomicon#512)
- Update to mdbook 0.5 (rust-lang/nomicon#511)

## reference

5 commits in b14b4e40f53ca468beaf2f5d0dfb4f4c4ba6bc7b..50c5de90487b68d429a30cc9466dc8f5b410128f
2025-12-02 21:17:44 +0000 to 2025-12-09 22:19:05 +0000
- UB: update the extra clause for provenance UB during const evaluation (rust-lang/reference#2091)
- Remove `[no-mentions]` handler in our triagebot config (rust-lang/reference#2102)
- Clarify that omitting `nostack` is a promise from the compiler to the programmer (rust-lang/reference#1999)
- Specify that range patterns must be nonempty. (rust-lang/reference#2093)
- Update to mdbook 0.5 (rust-lang/reference#2096)

## rust-by-example

1 commits in 111cfae2f9c3a43f7b0ff8fa68c51cc8f930637c..7d21279e40e8f0e91c2a22c5148dd2d745aef8b6
2025-11-27 17:16:42 -0300 to 2025-12-01 15:02:09 -0300
- Update to mdbook 0.5 (rust-lang/rust-by-example#1977)

Author: ChrisDenton