[clang] [clang-tools-extra] [compiler-rt] [flang] [lld] [lldb] [llvm] [mlir] [openmp] [pstl] Finally formalise our defacto line-ending policy (PR #86318)

[Adrian Prantl via cfe-commits]

adrian-prantl wrote:

While I'm sure this commit will manage to break _something_ unexpectedly, I think this is reasonable to do! Thanks for taking this on.

https://github.com/llvm/llvm-project/pull/86318