[libc++][chrono] Add calendar type formatters.
Some of the calendar types have landed before, this adds the missing
set. Note this does not complete the implementation of the chrono
formatters.
This removes the `chrono` header for some transitive include in C++17
mode. This is needed to avoid inclusion cycles.
Partially implements:
- P1361 Integration of chrono with text formatting
- P2372 Fixing locale handling in chrono formatters
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D137022
GitOrigin-RevId: 105fef5dca7ea224bf44a13ff3685fb1f3ae0876
36 files changed
