[libcxx-commits] [libcxx] [libc++] Add coding guidelines to the docs (PR #117051)

[Louis Dionne via libcxx-commits]

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

LGTM with the suggested changes.

This basically documents existing practice, so I feel like this should be fairly non-controversial. If someone wants to see changes, either raise it now or we can adjust post-commit.

https://github.com/llvm/llvm-project/pull/117051