Copy edits on the commit to avoid exposing this class in public API

Author: rafaelfranca

activerecord/lib/active_record/relation/query_methods.rb

@@ -120,17 +120,15 @@ def scope_association_reflection(association)
         end
     end
 
-    # A wrapper to distinguish CTE joins from other nodes
-    class CTEJoin
+    # A wrapper to distinguish CTE joins from other nodes.
+    class CTEJoin # :nodoc:
       attr_reader :name
 
       def initialize(name)
         @name = name
       end
     end
 
-    private_constant :CTEJoin
-
     FROZEN_EMPTY_ARRAY = [].freeze
     FROZEN_EMPTY_HASH = {}.freeze