Towards #182.
- This PR drops all section numbers except for D.x in `<yvals_core.h>`. I decided to cite WG21-N4868 for C++20 deprecation.
- Some citations in `<format>` are intentionally not updated because WG21-P2675R1 and LWG-3631 are not implemented yet.
- Citations in test files are not updated, but I think I'll do it soon.
- Drive-by change: a comment for `move_only_function`'s move assignment operator explaining why it's `noexcept(false)` (see https://github.com/microsoft/STL/pull/3565#discussion_r1134755402 and https://github.com/microsoft/STL/issues/2278#issuecomment-943360927).
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Co-authored-by: Stephan T. Lavavej <stl@nuwen.net>
Co-authored-by: Nicole Mazzuca <mazzucan@outlook.com>
Co-authored-by: Casey Carter <cacarter@microsoft.com>