[llvm] [Github] Do not label clang-format files as clang (PR #66388)

[Vlad Serebrennikov via llvm-commits]

Endilll wrote:

Totally agree, but we need to do something quickly, while number of PRs hasn't went out of hand (I see we have about 600-700 PRs a week), and we can fix things retroactively. I'm fine waiting for a better implementation (forking labeler), if there's anyone willing to get to it until the end of next week. Otherwise, I'll prepare brittle exclusion rules today.

I don't want our PRs end in the same sorry state as our bug tracker.

https://github.com/llvm/llvm-project/pull/66388