Fixed typos in docs/ref/models/constraints.txt.

docs/ref/models/constraints.txt

@@ -34,7 +34,7 @@ option.
 A :class:`Q` object that specifies the check you want the constraint to
 enforce.
 
-For example ``CheckConstraint(check=Q(age__gte=18), name='age_gte_18')``
+For example, ``CheckConstraint(check=Q(age__gte=18), name='age_gte_18')``
 ensures the age field is never less than 18.
 
 ``name``
@@ -59,8 +59,9 @@ The name of the constraint.
 A list of field names that specifies the unique set of columns you want the
 constraint to enforce.
 
-For example ``UniqueConstraint(fields=['room', 'date'], name='unique_location')``
-ensures only one location can exist for each ``date``.
+For example, ``UniqueConstraint(fields=['room', 'date'],
+name='unique_booking')`` ensures each room can only be booked once for each
+date.
 
 ``name``
 --------