Document the new TODOs feature

It would be very nice to understand what exactly gets on your TODO list and what does not. From my experimentation, self-assigning to an issue or even a self-mention in a comment does not cut it (this is, in my opinion, greatly decreases the utility of the TODO list, since this is rather a "what others think you are to do" list). But any particular opinions aside, the rules seem to be too complex to intuit, and the lack of documentation for the feature is detrimental.