Hi there,
Thanks a ton for writing in! Currently we do not have a way to annotate functions on the web app. However, we really appreciate feedback and feature requests; they help us decide what parts of our software development to prioritize. Here's the feature request forum we use to collect ideas:
http://seomoz.zendesk.com/forums/293194-seomoz-pro-feature-requests
You can vote for features you'd like to see and suggest your own, both of which help our product team in deciding what to build next. Add your request there and hopefully we'll see it come to fruition sometime down the line. Thanks again, and best of luck!
Have a great day,
Peter
Moz Help Team.