Thank you for the suggestion, but you can already do this:
https://forums.d2jsp.org/topic.php?t=78663873&f=28Quote
Added a feature that will allow you to add Bold, Red and Italic topic title features to an old topic. To do so simply edit your post and click "Preview Edit" or make a new post and click "Preview Post" and the options will appear (Apr 26 2018)