[clang] [llvm] [openmp] [Clang][OpenMP] Add `#pragma omp flatten` loop directive + `depth` clause (PR #206977)

[Jannick Kremer via llvm-commits]

https://github.com/DeinAlptraum commented:

I'm the maintainer for the libclang python bindings (cindex.py). That part LGTM

https://github.com/llvm/llvm-project/pull/206977