[libc++][ranges][NFC] Mark completed issues related to the One Ranges Proposal.

Quite a few C++20 LWG issues/papers related to the One Ranges Proposal
were already effectively implemented (or contain semantic-only wording
changes that don't affect the implementation), mark them as such.

Differential Revision: https://reviews.llvm.org/D125065

GitOrigin-RevId: 44ae09d75ffbf077aaad4bc1f6f75292fb5a1b52