Fix comment syntax

The code syntax in the comment example is invalid

railties/lib/rails/generators/rails/resource_route/resource_route_generator.rb

@@ -9,7 +9,7 @@ class ResourceRouteGenerator < NamedBase # :nodoc:
       # should give you
       #
       #   namespace :admin do
-      #     namespace :users
+      #     namespace :users do
       #       resources :products
       #     end
       #   end