[2.0.x] Fixed #28648 -- Corrected typo in docs/topics/db/queries.txt.

Backport of 293df73fb6 from master

docs/topics/db/queries.txt

@@ -228,7 +228,7 @@ refinements together. For example::
     ... ).exclude(
     ...     pub_date__gte=datetime.date.today()
     ... ).filter(
-    ...     pub_date__gte=datetime(2005, 1, 30)
+    ...     pub_date__gte=datetime.date(2005, 1, 30)
     ... )
 
 This takes the initial :class:`~django.db.models.query.QuerySet` of all entries