Add %b supoort

[Heshmatkhah]

Hi
Thank you for your great work.
Currently the %b in in fa_IR locale prints complete month name.
It's not common in Persian to abbreviate thing like month name, and you decision is completely makes sense.
But in my case short name is used due to space limitation and I need a 2-3 character month name.
So, please consider using something like this:

j_months_short_fa = [
    'فرو',
    'ارد',
    'خرد',
    'تیر',
    'مرد',
    'شهر',
    'مهر',
    'آبا',
    'آذر',
    'دی',
    'بهم',
    'اسف',
]