Describe the enhancement
While using the UpdateLocale Plugin, it isn't possible to just update one single value in a nested value.
For example I just want to update the format.L value:

dayjs.extend(UpdateLocale);
dayjs.updateLocale('de', {
  formats: {
    L: 'D.M.YYYY',
  },
});

Like this other formats LL, LLL, ... are getting lost.

Expected behavior
I want

Issue Description

Arrow does not seem to perform validation on timestamps for unusual formats where the information conflicts.

The following code snippet runs just fine:

>>> arrow.get("2021-01-30 14:00:00 AM", "YYYY-MM-DD hh:mm:ss A")
<Arrow [2021-01-30T14:00:00+00:00]>

First of all, since hh is documented to go to a maximum value of 12, I expect arrow to raise an err

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