As I am sure you are aware, you already have the ability to comment code using coment nodes. Also, if you expand most variables/functions/nodes there is a field there for comments as well. Given that all this functionality exists, and has since at least 4.5, I am not really certain what additional comment code you are looking for. Any details you add in the comment fields for variables/functions show up when you do mouseovers, even in the context menus.