[Components][EventDispatcher] describe the usage of the RegisterListenersPass

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | all
| Fixed tickets | #3879
I agree with @WouterJ you can also use it here $container->register('foo')->addTag('my.tag', array('hello' => 'world'));