Fix an omission in the recursive CTE documentation

activerecord/lib/active_record/relation/query_methods.rb

@@ -506,7 +506,7 @@ def with!(*args) # :nodoc:
     #
     #   Post.with_recursive(post_and_replies: [Post.where(id: 42), Post.joins('JOIN post_and_replies ON posts.in_reply_to_id = post_and_replies.id')])
     #   # => ActiveRecord::Relation
-    #   # WITH post_and_replies AS (
+    #   # WITH RECURSIVE post_and_replies AS (
     #   #   (SELECT * FROM posts WHERE id = 42)
     #   #   UNION ALL
     #   #   (SELECT * FROM posts JOIN posts_and_replies ON posts.in_reply_to_id = posts_and_replies.id)