[book][routing] Reworking explanation of the ClassName::showAction controller name format

The new explanation matches the quick tour more closely - where I felt it was explained very well

Author: weaverryan

book/routing.rst

@@ -804,14 +804,17 @@ The controller might look like this:
 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.
+
 .. note::
 
- Symfony also supports two other controller formats. The first contains
- one colon separator (e.g. ``service_name:indexAction``) and refers to
- the controller as a service (see :doc:`/cookbook/controller/service`).
- The second is formatted like ``ControllerClassName::methodName``. When
- Symfony sees this format, it will try to create a new instance of ``ControllerClassName``
- and then call the ``methodName`` method.
+ In addition to using the logical name or the fully-qualified class name,
+ Symfony supports a third way of referring to a controller. This method
+ uses just one colon separator (e.g. ``service_name:indexAction``) and
+ refers to the controller as a service (see :doc:`/cookbook/controller/service`).
 
 Route Parameters and Controller Arguments
 -----------------------------------------