Add a test for the geo-enabled inspectdb command
Fixed inspectdb test for spatialite >=4
Fixed #21099 - Skip DistinctOnTests unless backend can_distinct_on_fields
Merge pull request #1622 from manfre/ticket-21099

Fixed #21099 - Skip DistinctOnTests unless backend can_distinct_on_field...
Fixed a couple of typos in GeoDjango docs.
Refactored admin's autodiscover method to make it reusable.

We want to be able to use it for instance for discovering `tasks.py` modules
inside the INSTALLED_APPS.

This commit therefore moves the logic to `autodiscover_modules` method in
django.utils.module_loading.

This closes ticket #21060.