[1.4.X] Fixed #18548 - Clarified note regarding reusing model instances when form validation fails.
[1.4.X] Fixed #18548 - Clarified note regarding reusing model instances when form validation fails.

Backport of fd02bcff4a from master

riklaunim/django-custom-multisite,riklaunim/django-custom-multisite,riklaunim/django-custom-multisite