Update explanation of the attribute option

Author: mdoutreluingne

security/access_control.rst

@@ -30,7 +30,7 @@ options are used for matching:
 * ``host``: a regular expression
 * ``methods``: one or many HTTP methods
 * ``request_matcher``: a service implementing ``RequestMatcherInterface``
-* ``attributes``: is an array, which can be used to specify attributes of the query
+* ``attributes``: an array, which can be used to specify one or more :ref:`request attributes <accessing-request-data>` that must match exactly
 * ``route``: a route name
 
 .. versionadded:: 6.1