Fix typo in the documentation

Author: rafaelfranca

actionview/lib/action_view/model_naming.rb

@@ -2,7 +2,7 @@
 
 module ActionView
   module ModelNaming # :nodoc:
-    # Converts the given object to an ActiveModel compliant one.
+    # Converts the given object to an Active Model compliant one.
     def convert_to_model(object)
       object.respond_to?(:to_model) ? object.to_model : object
     end