Description of the new feature/enhancement

Have some kind of popup which lets you know that you can use ctrl + shift + c/v the first time a user presses either of those key commands. I'm a fresh convert from macOS and eventually found out you could right click to paste, but it too searching and finding https://github.com/microsoft/terminal/issues/968 till I found out the key commands.

There's a case for when you ctrl + c to close a process, but I think showing it once is an acceptable trade-off (you might also know if there's a running process which it could close) and for ctrl + v that's a NOOP, so doing something there is an easy win

Proposed technical implementation details (optional)

Probably not relevant