Rollup of 16 pull requests

[Centril]

Successful merges:

• Stabilize the alloc crate. #59675 (Stabilize the alloc crate.)
• Mark variables captured by reference as mutable correctly #59708 (Mark variables captured by reference as mutable correctly)
• remove lookup_char_pos_adj #59735 (remove lookup_char_pos_adj)
• Copy book.toml unstable book generator #59747 (Copy book.toml unstable book generator)
• Retire IsNotConst naming #59796 (Retire IsNotConst naming)
• Eliminate FnBox usages from libstd. #59818 (Eliminate FnBox usages from libstd.)
• Fix links on keyword docs. #59830 (Fix links on keyword docs.)
• Re-export NonZero signed variant in std #59835 (Re-export NonZero signed variant in std)
• std: Add {read,write}_vectored for more types #59852 (std: Add {read,write}_vectored for more types)
• Fix attributes position in type declaration #59855 (Fix attributes position in type declaration)
• Make duplicate matcher bindings a hard error #59858 (Make duplicate matcher bindings a hard error)
• Add a comment explaining why SecRandomCopyBytes is not used on MacOS #59879 (Use SecRandomCopyBytes instead of /dev/urandom on MacOS)
• In -Zprint-type-size output, sort enum variants by size. #59899 (In -Zprint-type-size output, sort enum variants by size.)
• MaybeUninit: remove deprecated functions #59912 (MaybeUninit: remove deprecated functions)
• Fix paste error in split_ascii_whitespace docs. #59925 (Fix paste error in split_ascii_whitespace docs.)
• Exclude some copies of old book editions from search engines #59930 (Exclude some copies of old book editions from search engines)

Failed merges:

r? @ghost