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

[Louis Dionne via cfe-commits]

ldionne wrote:

Gentle ping. There's outstanding feedback to address on this review. @ZijunZhaoCCK if you don't think you'll have time to pursue this PR anymore, it's all good but please let us know so we can assign it to someone else!

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