Issue with FOLLOW object in Lua script for rover to follow copter

Thanks @Yuri_Rage for the investigation.

I don’t think that there’s any reason why we can’t enable this for Rover so I think it’s just a small change to add Rover to that list of available vehicles.

I could raise a PR to change that or anyone else could as well I think

P.S. I’ve moved this to the Rover-4.6 category instead of “General”