Yes, but I don't know how effective it is. 99% of the time someone leaves a 'nit' the other person fixes it. So we're still dealing with most of them like regular comments. Only once or twice I've been like "nah, I like my way better" but I can only do that if they also leave an LGTM. Sometimes they do. There's one or two people that will hold your code hostage until you reply to every little nit. At that point they don't feel like nits. I always LGTM if the code is functionally correct or if the build breaks in a trivial way (that would also block them from submitting). Then they can address my nits or submit anyway and I'm cool with that.

Yes it is. I've really oijed those convention at places I've worked. It probably wouldn't be too hard to instruct AI's to use this format too.