Documentation changes for search_fields.
Documentation changes for search_fields.

--HG--
branch : multi-field-lookups

makinacorpus/django-selectable,affan2/django-selectable,affan2/django-selectable,mlavin/django-selectable,mlavin/django-selectable,affan2/django-selectable,mlavin/django-selectable,makinacorpus/django-selectable