Unused var and val highlighting

[Trinsdar]

Would yoy be able to make it so that if a val or var variable is not used anywhere in the file it will show greyed out so to indicate it's not being used? kinda like how in intellj idea greys out unused variables like this:

first is unused, second is used. doesn't have to be exactly like that, as long as I can tell that it's not used then that's good enough for me.