Include documentation from event listener methods in module canvas

A typical event listener method looks like this:

```java
@Component
class MyEventListeners {

  /**
   * Some documentation about what this does.
   *
   * @param event
   */
  @EventListener
  void on(SomethingHappened event) { &hellip; }
}
```

It would be cool if the method comment was included in the module canvas generated and listed under the event listeners section.