Add versionadded

Author: jmsche

form/form_customization.rst

@@ -124,6 +124,10 @@ control the generated HTML without having to deal with form themes:
         {% endfor %}
     </select>
 
+.. versionadded:: 5.2
+
+    The ``field_*()`` helpers were introduced in Symfony 5.2.
+
 Form Rendering Variables
 ------------------------