fix event

Author: oblomov-dev

docs/development/navigation/app_state.md

@@ -27,7 +27,7 @@ CLASS z2ui5_cl_sample_app_state IMPLEMENTATION.
             )->input( client->_bind_edit( mv_quantity )
             )->button(
                 text  = `post with state`
-                press = client->_event( val = `BUTTON_POST` )
+                press = client->_event( `BUTTON_POST` )
               )->stringify( ) ).
     ENDIF.