Add examples of `prepend_ee_mod` usage

app/controllers/application_controller.rb

@@ -556,4 +556,4 @@ class ApplicationController < ActionController::Base
   end
 end
 
-ApplicationController.prepend_if_ee('EE::ApplicationController')
+ApplicationController.prepend_ee_mod

app/models/vulnerability.rb

@@ -25,4 +25,4 @@ class Vulnerability < ApplicationRecord
   end
 end
 
-Vulnerability.prepend_if_ee('EE::Vulnerability')
+Vulnerability.prepend_ee_mod

lib/api/api.rb

@@ -313,4 +313,4 @@ module API
   end
 end
 
-API::API.prepend_if_ee('::EE::API::API')
+API::API.prepend_ee_mod