[symfony#4805] Adding versionadded

Author: weaverryan

reference/twig_reference.rst

@@ -361,6 +361,9 @@ information in :ref:`book-templating-pages`.
 absolute_url
 ~~~~~~~~~~~~
 
+.. versionadded:: 2.6
+     The ``absolute_url`` function was introduced in Symfony 2.7
+
 .. code-block:: jinja
 
     {{ absolute_url(path) }}
@@ -378,6 +381,9 @@ an existing path:
 relative_path
 ~~~~~~~~~~~~~
 
+.. versionadded:: 2.6
+     The ``relative_path`` function was introduced in Symfony 2.7
+
 .. code-block:: jinja
 
     {{ relative_path(path) }}