I added support for this in Damus, but only did the decoding part of it. At that time (maybe different now) Damus didn’t have seem to have a simple way to make relay URLs interactive. Would be nice if you could tap and then have an option to add it to your list of relays. But currently it just shows the URL
Discussion
It is the same story in gossip currently. It just renders the url, but it's not clickable into anything (there are no wss:// handlers), and I plan to make it open the relay configuration page for that relay (which we don't have yet as a separate page, so of course I can't do that yet).