Fixed #27850 -- Made RelatedFieldWidgetWrapper call render() of the wrapped widget.

django/forms/widgets.py

@@ -5,7 +5,6 @@ HTML Widget classes
 import copy
 import datetime
 import re
-from contextlib import contextmanager
 from itertools import chain
 
 from django.conf import settings
@@ -630,13 +629,6 @@ class ChoiceWidget(Widget):
                 pass
         return getter(name)
 
-    @contextmanager
-    def override_choices(self, choices):
-        old = self.choices
-        self.choices = choices
-        yield
-        self.choices = old
-
     def format_value(self, value):
         """Return selected values as a set."""
         if not isinstance(value, (tuple, list)):