Rollup merge of rust-lang#140676 - rustbot:docs-update, r=ehuss

Update books

## rust-lang/reference

9 commits in 3bf3402aea982b876eb56c87da17b0685c6461d5..387392674d74656f7cb437c05a96f0c52ea8e601
2025-05-03 21:29:09 UTC to 2025-04-22 15:25:03 UTC

- Document `let_chains` again (rust-lang/reference#1740)
- Add: orphan rule rationale. (rust-lang/reference#1755)
- Remove apologies about the Reference (rust-lang/reference#1792)
- Clean up some inline assembly examples (rust-lang/reference#1804)
- Remove StructExprTuple and StructExprUnit (rust-lang/reference#1803)
- Improve documentation of struct expressions (rust-lang/reference#1799)
- Clarify interaction of asm-goto with IBT (rust-lang/reference#1790)
- naked functions (rust-lang/reference#1689)
- Relabel grammarRailroad-Button (rust-lang/reference#1798)

## rust-lang/rust-by-example

3 commits in 0d7964d5b22cf920237ef1282d869564b4883b88..8a8918c698534547fa8a1a693cb3e7277f0bfb2f
2025-04-30 12:20:49 UTC to 2025-04-22 17:42:30 UTC

-   The example is not meant to be compiled. Changed the code block ann… (rust-lang/rust-by-example#1926)
- Non-tail recursive call note in testcase_linked_list.md (rust-lang/rust-by-example#1924)
- docs: mark illustrative 'static lifetime example with `ignore` (rust-lang/rust-by-example#1923)

Author: GuillaumeGomez