minor #6006 [Book] use AppBundle examples and follow best practices (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Book] use AppBundle examples and follow best practices

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

Commits
-------

2394e3f use AppBundle examples and follow best practices

Author: wouterj

book/from_flat_php_to_symfony2.rst

@@ -554,7 +554,7 @@ them for you. Here's the same sample application, now built in Symfony::
         {
             $posts = $this->get('doctrine')
                 ->getManager()
-                ->createQuery('SELECT p FROM AcmeBlogBundle:Post p')
+                ->createQuery('SELECT p FROM AppBundle:Post p')
                 ->execute();
 
             return $this->render('Blog/list.html.php', array('posts' => $posts));

book/page_creation.rst

@@ -191,7 +191,7 @@ at the end:
 
     .. code-block:: xml
 
-        <!-- src/Acme/DemoBundle/Resources/config/routing.xml -->
+        <!-- app/config/routing.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <routes xmlns="http://symfony.com/schema/routing"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -205,7 +205,7 @@ at the end:
 
     .. code-block:: php
 
-        // src/Acme/DemoBundle/Resources/config/routing.php
+        // app/config/routing.php
         use Symfony\Component\Routing\RouteCollection;
         use Symfony\Component\Routing\Route;
 

book/routing.rst

@@ -1110,9 +1110,9 @@ Notice that Symfony adds the string ``Controller`` to the class name (``Blog``
 => ``BlogController``) and ``Action`` to the method name (``show`` => ``showAction``).
 
 You could also refer to this controller using its fully-qualified class name
-and method: ``Acme\BlogBundle\Controller\BlogController::showAction``.
-But if you follow some simple conventions, the logical name is more concise
-and allows more flexibility.
+and method: ``AppBundle\Controller\BlogController::showAction``. But if you
+follow some simple conventions, the logical name is more concise and allows
+more flexibility.
 
 .. note::