[1.0.X]: Fixed #10375 -- Added documentation about the default format strings...

[1.0.X]: Fixed #10375 -- Added documentation about the default format strings used for the `date` and `time` filters when no format string is passed to the filter, based on patch from kgrandis.

Backport of r10259 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10260 bcc190cf-cafb-0310-a4f2-bffc1f526a37