Update authorization.rst

Author: zairigimad

components/security/authorization.rst

@@ -47,7 +47,7 @@ recognizes several strategies:
     grant access if there are more voters granting access than there are denying;
 
 ``unanimous``
-    only grant access if none of the voters has denied access;
+    only grant access if none of the voters has denied access. If all voters abstained from voting, the decision is based on the ``allow_if_all_abstain`` config option (which defaults to ``false``);
 
 Usage of the available options in detail::