Translation is not working for other languages.

[Ibrohimbek]

When I changed user language in my project to Spanish I got an exception because of translated variable in line reccurence/base.py:1191:

_('every %(number)s %(freq)s') % {
                'number': rule.interval,
                'freq': timeintervals[rule.freq]
            }

There are used old python formatting that needed to upgrade.
There are other places that needed to upgrade of formating.

Changing that line to this fixes the problem:

_(f"every {rule.interval} {timeintervals[rule.freq]}")