Document the class methods include module for AJ::Callbacks [ci skip]

activejob/lib/active_job/callbacks.rb

@@ -22,6 +22,8 @@ module ActiveJob
       define_callbacks :enqueue
     end
 
+    # These methods will be included into any Active Job object, adding
+    # callbacks for `perform` and `enqueue` methods.
     module ClassMethods
       # Defines a callback that will get called right before the
       # job's perform method is executed.