libstdc++: Add _GLIBCXX_RESOLVE_LIB_DEFECTS comments for 2023 issues.

Covers issues affecting pre-C++23 features that was accepted during
meetings in year 2023.

libstdc++-v3/ChangeLog:

	* include/bits/version.def (allocate_at_least): Add comment
	listing papers adding values and LWG3887.
	* include/bits/stl_iterator.h: Add comment for LWG3953.
	* include/std/format: Add comment for LWG3892.
	* include/std/type_traits: Add comment for LWG3655.