RepeatedType overrides mapped value for the type to work properly

Author: biozshock

reference/forms/types/repeated.rst

@@ -129,6 +129,11 @@ the label::
         'second_options' => ['label' => 'Repeat Password'],
     ]);
 
+.. note::
+
+    The ``mapped`` option is overridden for both fields in order for the type
+    to work properly
+
 ``options``
 ~~~~~~~~~~~