[libcxx] adds `std::incrementable_traits` to <iterator>

Implements parts of:
    - P0896R4 The One Ranges Proposal

Depends on D99041

Differential Revision: https://reviews.llvm.org/D99141

GitOrigin-RevId: fe31f11cc82135a9f612300a66fd6b80cc3245c3
4 files changed