[clang] [Clang] Add warning for non-portable include paths with trailing whitespace or dots (PR #190610)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

Oh, it seems CI is stuck though so auto-merge isn't going to work too well for us. I can't figure out how to get to that job to manually re-run it, so I think we need @ameliajochna to push a merge commit to restart CI.

https://github.com/llvm/llvm-project/pull/190610