[libcxx-commits] [libcxx] [libc++] Optimize char_traits a bit (PR #72799)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne approved this pull request.

LGTM assuming we already have appropriate coverage in char_traits for `char8_t` and friends.

https://github.com/llvm/llvm-project/pull/72799