minor #6591 5953 use kernel events constants (snoek09)

This PR was squashed before being merged into the 2.3 branch (closes #6591).

Discussion
----------

5953 use kernel events constants

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #5953

Commits
-------

ad0e377 5953 use kernel events constants

Author: wouterj

components/event_dispatcher/container_aware_dispatcher.rst

@@ -68,14 +68,15 @@ and the second argument is the service's class name (which must implement
 The ``EventSubscriberInterface`` is exactly as you would expect::
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+    use Symfony\Component\HttpKernel\KernelEvents;
     // ...
 
     class StoreSubscriber implements EventSubscriberInterface
     {
         public static function getSubscribedEvents()
         {
             return array(
-                'kernel.response' => array(
+                KernelEvents::RESPONSE => array(
                     array('onKernelResponsePre', 10),
                     array('onKernelResponsePost', 0),
                 ),
@@ -98,3 +99,4 @@ The ``EventSubscriberInterface`` is exactly as you would expect::
             // ...
         }
     }
+

cookbook/event_dispatcher/event_listener.rst

@@ -142,14 +142,15 @@ listen to the same ``kernel.exception`` event::
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
     use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
+    use Symfony\Component\HttpKernel\KernelEvents;
 
     class ExceptionSubscriber implements EventSubscriberInterface
     {
         public static function getSubscribedEvents()
         {
             // return the subscribed events, their methods and priorities
             return array(
-               'kernel.exception' => array(
+               KernelEvents::EXCEPTION => array(
                    array('processException', 10),
                    array('logException', 0),
                    array('notifyException', -10),

create_framework/http_kernel_httpkernel_class.rst

@@ -150,8 +150,9 @@ only if needed::
     namespace Simplex;
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-    use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
     use Symfony\Component\HttpFoundation\Response;
+    use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
+    use Symfony\Component\HttpKernel\KernelEvents;
 
     class StringResponseListener implements EventSubscriberInterface
     {
@@ -166,7 +167,7 @@ only if needed::
 
         public static function getSubscribedEvents()
         {
-            return array('kernel.view' => 'onView');
+            return array(KernelEvents::VIEW => 'onView');
         }
     }