Add "Double posted" to list of reasons for topic removal

Whenever we remove a topic, we're required to check off a reason why the topic is being removed. One of the most common reasons why we remove a topic is because it has been double posted due to the poster clicking on submit more than once.

It would be great if there were a "Double Posted" or "Duplicate Post" as a reason for removing a topic because "Spam" or other reasons in the list don't really fit why we deleted the post.

Thanks!