[llvm] [libcxx] [lld] [flang] [compiler-rt] [clang-tools-extra] [clang] [libc++][ranges] P2116R9: Implements `views::enumerate` (PR #73617)

[Christopher Di Bella via cfe-commits]

https://github.com/cjdb requested changes to this pull request.

Thanks for working on this! There's a fair bit that I've provided comments for, but I think you're off to a great start, and I would like to see this merged in January, if at all possible.

Some comments are short and repetitive: those are usually coupled with a starter comment that explains my perspective, and then I just flag the others as I see them in a (hopefully) non-intrusive way.

https://github.com/llvm/llvm-project/pull/73617