Rollup merge of #156152 - rustbot:docs-update, r=ehuss

Update books

## rust-lang/reference

4 commits in 8c88f9d0bdd75ffdc0691676d83212ae22a18cee..581920f9109f141b88b860b3e1e8359e3896a150
2026-04-30 02:40:57 UTC to 2026-04-28 16:48:51 UTC

- Document trailing `self` in paths (rust-lang/reference#2237)
- add trailing comma (to follow style guidelines) (rust-lang/reference#2244)
- Doc: Add the LoongArch stabilized target features (rust-lang/reference#2217)
- typo (rust-lang/reference#2241)