Not clear that non-ISO calendars should reject month codes that don't exist #3163
Description
The ISO calendar rejects month codes that aren't M01 through M12 in CalendarResolveFields.
However, I don't see in NonISOResolveFields where this rejection should happen. There are examples of cases that should reject, but this is not one of them, as far as I can see.
I confirmed on Matrix that the champions believe that non-ISO calendars should reject month codes that don't exist in their calendar (like "gregory" rejecting "M13" or "M01L").