[1.8.x] Fixed #26233 -- Fixed invalid reSt in models.Q docstring.

Backport of 70d3f81ca4ea7e1e1310e13ce0a633d7f920d45b from master

django/db/models/query_utils.py

@@ -42,7 +42,7 @@ class QueryWrapper(object):
 class Q(tree.Node):
     """
     Encapsulates filters as objects that can then be combined logically (using
-    & and |).
+    `&` and `|`).
     """
     # Connection types
     AND = 'AND'