Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/modules/action/action.api.php

@@ -5,6 +5,11 @@
  * Hooks provided by the Actions module.
  */
 
+/**
+ * @addtogroup hooks
+ * @{
+ */
+
 /**
  * Executes code after an action is deleted.
  *
@@ -16,3 +21,7 @@ function hook_action_delete($aid) {
     ->condition('aid', $aid)
     ->execute();
 }
+
+/**
+ * @} End of "addtogroup hooks".
+ */