Fixed #23055 -- Made generic admin filter obey ModelAdmin queryset.

Thanks to Trac user synasius and to Ola Sitarska for helping in
identifying the issue and helping with the test case.
Fixed #22820 -- Treated int and long types alike in lazy_number

Thanks kwist for the report and the initial patch.
Added a missing word in a skip message
Fixed #23388 -- Made django.utils.timezone.override usable as a decorator
Removed sentence from docs about migrate prompting to add a superuser.
Fixed #23391 -- Removed an erroneous backtip from the form's documentation.

Thanks to Trac alias nessita for the report.