If you know of an Emacs extension that does these, I would be very happy to know about it. These days I'm programming 100% in Emacs for various reasons, so I looked quite a bit (though it's true that was a few years ago now, so maybe some have turned up).

LSP itself certainly doesn't support this, though they can probably be built on top of it with some effort. For that matter, I also don't think VSCode supports them, though I have used Emacs far far more than that.