[clang] [compiler-rt] [libcxx] [lld] [lldb] [llvm] [mlir] [polly] python: use raw strings for regex (PR #105990)

[Tobias Hieta via cfe-commits]

tru wrote:

This was suggested in https://github.com/llvm/llvm-project/pull/91856 and the suggestion there was that we need to split it up per sub-project which is something @e-kwsm has been doing: https://github.com/llvm/llvm-project/pulls/e-kwsm so I don't think this one is needed.

https://github.com/llvm/llvm-project/pull/105990