[libcxx-commits] [libcxx] [libc++] Remove abandoned __append declaration in vector<bool> (PR #121673)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 approved this pull request.

Looks like it's been there since the initial import and was never defined.

https://github.com/llvm/llvm-project/pull/121673