Fixed #26837 -- Documented ModelMultipleChoiceField.to_field_name

docs/ref/forms/fields.txt

@@ -1207,13 +1207,19 @@ method::
     Allows the selection of one or more model objects, suitable for
     representing a many-to-many relation. As with :class:`ModelChoiceField`,
     you can use ``label_from_instance`` to customize the object
-    representations, and ``queryset`` is a required parameter:
+    representations.
+
+    A single argument is required:
 
     .. attribute:: queryset
 
-        A ``QuerySet`` of model objects from which the choices for the
-        field will be derived, and which will be used to validate the
-        user's selection.
+        Same as :class:`ModelChoiceField.queryset`.
+
+    Takes one optional argument:
+
+    .. attribute:: to_field_name
+
+        Same as :class:`ModelChoiceField.to_field_name`.
 
 Creating custom fields
 ======================