[libcxx-commits] [libcxx] [libc++][docs] Mark LWG3116 as Complete (PR #209916)

[Louis Dionne via libcxx-commits]

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

In the PR description, please explain why this is already done and no tests need to be added.

https://github.com/llvm/llvm-project/pull/209916