document generators hidden_namespaces

railties/lib/rails/generators.rb

@@ -160,6 +160,11 @@ def self.invoke(namespace, args=ARGV, config={})
       end
     end
 
+    # Returns an array of generator namespaces that are hidden.
+    # Generator namespaces may be hidden for a variety of reasons.
+    # Some are aliased such as "rails:migration" and can be
+    # invoked with the shorter "migration", others are private to other generators
+    # such as "css:scaffold".
     def self.hidden_namespaces
       @hidden_namespaces ||= begin
         orm      = options[:rails][:orm]