[libcxx-commits] [libcxx] [libc++][NFC] Granularize includes of <optional> (PR #213433)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 requested changes to this pull request.

This isn't NFC, since it removes transitive includes.

https://github.com/llvm/llvm-project/pull/213433