[lldb][libc++] Adds missing C++20 calendar data formatters. (#77954)

This is a followup of #76983 and adds the libc++ data formatters for
- weekday,
- weekday_indexed,
- weekday_last,
- month_weekday,
- month_weekday_last,
- year_month,
- year_month_day_last
- year_month_weekday, and
- year_month_weekday_last.