restore the how to NOT do it example in the "Service: No Class Parameter" section

Author: uvoelkel

best_practices/business-logic.rst

@@ -140,9 +140,12 @@ the class namespace as a parameter:
     # app/config/services.yml
 
     # service definition with class namespace as parameter
+    parameters:
+    slugger.class: AppBundle\Utils\Slugger
+
     services:
         app.slugger:
-            class: AppBundle\Utils\Slugger
+            class: "%slugger.class%"
 
 This practice is cumbersome and completely unnecessary for your own services: