Fix PHPCS error and add doc block.

src/Controller/Component.php

@@ -23,11 +23,19 @@
  * controller logic that can be composed into a controller. Components also
  * provide request life-cycle callbacks for injecting logic at specific points.
  *
+ * ## Initialize hook
+ *
+ * Like Controller and Table, this class has an initialize() hook that you can use
+ * to add custom 'constructor' logic. It is important to remember that each request
+ * (and sub-request) will only make one instance of any given component.
+ *
  * ## Life cycle callbacks
  *
  * Components can provide several callbacks that are fired at various stages of the request
  * cycle. The available callbacks are:
  *
+ * - `beforeFilter(Event $event)`
+ *   Called before the controller's beforeFilter method by default.
  * - `startup(Event $event)`
  *   Called after the controller's beforeFilter method, and before the
  *   controller action is called.
@@ -106,6 +114,7 @@ public function __construct(ComponentRegistry $registry, array $config = []) {
  * Implement this method to avoid having to overwrite
  * the constructor and call parent.
  *
+ * @param array $config The configuration array this component is using.
  * @return void
  */
 	public function initialize(array $config) {