[clang] [clang-tools-extra] [clang-tidy] Avoid matching nodes in system headers (PR #151035)

[Julian Schmidt via cfe-commits]

https://github.com/5chmidti approved this pull request.

LGTM. This will be super nice to have, and should also help make clang-tidy checks in clangd more responsive (when using system includes)

> @5chmidti Here goes 2 more seconds :)

XD

https://github.com/llvm/llvm-project/pull/151035