go/doc/next/6-stdlib/99-minor/regexp/syntax/70781.md

The \p{name} and \P{name} character class syntaxes now accept the names Any, ASCII, Assigned, Cn, and LC, as well as Unicode category aliases like \p{Letter} for \pL. Following Unicode TR18, they also now use case-insensitive name lookups, ignoring spaces, underscores, and hyphens.