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

[via llvm-commits]

ldrumm wrote:

@AaronBallman you said this has happened before, but I don't see this in history. Can you link to the commit to which you're referring?

I only see one other commit (9783f28cb) that touches the root `.gitattributes`

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