Add reference to documentation in FormEvents phpdocs

Author: ifdattic

src/Symfony/Component/Form/FormEvents.php

@@ -11,6 +11,12 @@
 namespace Symfony\Component\Form;
 
 /**
+ * To learn more about how form events work check the documentation
+ * entry at {@link http://symfony.com/doc/current/components/form/form_events.html}
+ *
+ * To learn how to dynamically modify forms using events check the cookbook
+ * entry at {@link http://symfony.com/doc/current/cookbook/form/dynamic_form_modification.html}
+ *
  * @author Bernhard Schussek <[email protected]>
  */
 final class FormEvents