[libcxx-commits] [libcxx] [libc++][test][NFC] Clang-format `<regex>` tests (PR #164367)

[Louis Dionne via libcxx-commits]

ldionne wrote:

@philnik777 Really, we should be formatting the whole code base. It's just that the patch that does that is going to be humongous, not even reviewable on Github. There's too much code.

As a result, we've been reformatting smaller bits and pieces from time to time, and I think that's acceptable, if done as their own separate patch (which can then be added to `.git-blame-ignore-revs`.

https://github.com/llvm/llvm-project/pull/164367