Customize which events can (or cannot) affect the "latest timestamp" for a room

I'd like it if the "Latest" value in the room list represented the most recent message, but I think it reflects *any* event, including things like "someone changed their username", making it annoying to check the room to see what's new and find that the answer is "absolutely nothing of interest".

It would be really nice if you could constrain which events triggered a change to the timestamp for the room list purposes.

I got as far as looking at `ement--push-joined-room-events` and the `push-events / setf latest-timestamp` code, but I don't understand the Matrix API so I can only hand-wave about some kind of conditional code at that point (or maybe a second, new timestamp just for the room listing).