CodeStyle fixes

Author: mtarld

service_container/service_decoration.rst

@@ -314,7 +314,7 @@ The generated code will be the following::
     $this->services[Foo::class] = new Baz(new Bar(new Foo()));
 
 Control the behavior when the decorated service does not exist
--------------------
+--------------------------------------------------------------
 
 Let's imagine you have a decorator that decorates a service defined in another bundle.
 If for some reasons, that bundle is missing, the ``decoration_on_decorated_invalid``