Replace Mobility::Translates module with simple def on extending class

lib/mobility.rb

@@ -38,7 +38,9 @@ class VersionNotSupportedError < ArgumentError; end
 
   class << self
     def extended(model_class)
-      model_class.extend Translates
+      def model_class.translates(*args, **options)
+        include Mobility.translations_class.new(*args, **options)
+      end
     end
 
     # Extends model with this class so that +include Mobility+ is equivalent to
@@ -177,17 +179,6 @@ def set_locale(locale)
     end
   end
 
-  module Translates
-    # Includes translated attributes on model class.
-    # @!method translates(*attributes, **options)
-    #   @param [Array<String>] attributes
-    #   @param [Hash] options
-    #   @yield Yields to block with backend as context
-    def translates(*args, **options)
-      include Mobility.translations_class.new(*args, **options)
-    end
-  end
-
   class InvalidLocale < I18n::InvalidLocale; end
   class NotImplementedError < StandardError; end
 end

lib/mobility/translations.rb

@@ -7,9 +7,9 @@ module Mobility
 Module containing translation accessor methods and other methods for accessing
 translations.
 
-Normally this class will be created by calling
-{Mobility::Translates#translates}, which is a class method on any model that
-extends {Mobility}, but it can also be used independent of that macro.
+Normally this class will be created by calling +translates+ on the model class,
+added when extending {Mobility}, but it can also be used independent of that
+macro.
 
 ==Including Translations in a Class