fix YYYY formatting

[safareli]

No description provided.

[cryogenian]

LGTM, what's the way of formatting years as is, I.e. 19 -> 19? I didn't see 0019 before

[safareli]

what's the way of formatting years as is, I.e. 19 -> 19

I guess YearAbsolute.

I didn't see 0019 before

motivation behind this pr is that when we have format YYYY (YearFull) and we parse we expect to have 4 digits in input string. but when we format, we can't parse it again as parser expects 4 digits to be present. alternative option will be to not require 4 digits:

- (parseInt 4 exactLength "Incorrect full year")
+ (parseInt 4 empty "Incorrect full year")

I.e. don't ask for exact 4 digits and parse up to 4 digits (now I think it will be much better).

Will close this and open another pr to remove exactLength from year parser

[safareli]

#24 (comment)

@cryogenian Approve if you like and will merge then.