Fixed #12313 - Add a note that QuerySet.delete() doesn't necessarily call obj.delete(). thanks FunkyELF for the suggestion.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15071 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/db/models.txt

@@ -751,6 +751,14 @@ built-in model methods, adding new arguments. If you use ``*args,
 **kwargs`` in your method definitions, you are guaranteed that your
 code will automatically support those arguments when they are added.
 
+.. admonition:: Overriding Delete
+
+    Note that the :meth:`~Model.delete()` method for an object is not
+    necessarily called when :ref:`deleting objects in bulk using a
+    QuerySet<topics-db-queries-delete>`. To ensure customized delete logic
+    gets executed, you can use :data:`~django.db.models.signals.pre_save`
+    and/or :data:`~django.db.models.signals.post_save` signals.
+
 Executing custom SQL
 --------------------