Describe the bug
dayjs does not have function types in Typescript.

Expected behavior
With localeData plugin included, dayjs should have the declaration of functions below.

dayjs.weekdays()
dayjs.weekdaysShort()
dayjs.weekdaysMin()
dayjs.monthsShort()
dayjs.months()

Information

• Day.js Version 1.8.33
• OS: Mac
• Browser Chrome 85
• Time zone: GMT+11:00

The implementation of span_range (and also interval()) is surprising to me, and is not what I would expect from a range function.

            >>> start = datetime(2013, 5, 5, 12, 30)
            >>> end = datetime(2013, 5, 5, 17, 15)
            >>> for r in arrow.Arrow.span_range('hour', start, end):
            ...     print(r)
            ...
            (<Arrow [2013-05-05T12:00:0

I'd like an /Examples folder with some simple iOS apps showing how to use Time.

The first one that comes to mind is a basic iOS app using a UICollectionView to build a month calendar view.

This is related to #410 and #859, we currently only support a limited subset of possible values for RDATE, but we should support all the parameters in RDATE, the grammar for which is set out in RFC 5545:

       rdate      = "RDATE" rdtparam ":" rdtval *("," rdtval) CRLF

       rdtparam   = *(
                  ;
                  ; T