Add a versionadded note

Author: Dinduks

reference/forms/types/options/escape_label.rst.inc

@@ -2,6 +2,9 @@ escape_label
 ~~~~~~~~~~~~
 **type**: ``Boolean``  **default**: ``true``
 
+.. versionadded:: 2.1
+    The ``escape_label`` option is new in Symfony 2.1.
+
 If set to false, the label's content won't be escaped. This option is useful when wanting to use HTML tags inside a label.
 
 .. code-block:: php