Updated scaffold_controller generator docs #7146

It was just a copy of the controller generator documentation which was
misleading.  It doesn't accept arguments for views.  This seems more
descriptive as well.

Respect 80 char limit. #7147

Made a nicer paragraph #7147

railties/lib/rails/generators/rails/scaffold_controller/USAGE

 Description:
-    Stubs out a scaffolded controller and its views. Pass the model name,
-    either CamelCased or under_scored, and a list of views as arguments.
-    The controller name is retrieved as a pluralized version of the model
-    name.
+    Stubs out a scaffolded controller, its seven RESTful actions and related
+    views. Pass the model name, either CamelCased or under_scored. The
+    controller name is retrieved as a pluralized version of the model name.
 
     To create a controller within a module, specify the model name as a
     path like 'parent_module/controller_name'.