[libcxx] [clang] [lld] [clang-tools-extra] [lldb] [mlir] [compiler-rt] [llvm] [libc++][ranges] Implement ranges::contains_subrange (PR #66963)

[Mark de Wever via cfe-commits]

https://github.com/mordante commented:

Thanks for your patch!
I mainly glossed over the patch, and left some comments.

https://github.com/llvm/llvm-project/pull/66963