I'm a little confused about the correct way to notify the OP and the community of duplicate questions. The highest-voted answer in the question How to handle duplicate questions? and official FAQ state:
If you have edit powers add the following at the top of the question:
> [title of question](url to question)
At the moment links to possible duplicates are inserted in the question text once a question is closed.
So does that mean if I edit the post to add the duplicate and then it is closed, the 'Duplicate' markers will be added twice? Is the FAQ out-of-date and is there a different way we should be notifying of duplicates?