(Java) Current world name display in Pause Menu

The name of the world that you're playing on should show up when you enter the pause menu. If you pause while on a server, it could display the name you gave it in the multiplayer list instead.

This would be helpful if you have a lot of similar worlds (e.g. for testing purposes) and prevent you from having to log out just to see which world you were playing.

Basic mockup: https://i.imgur.com/tTnmu0P.png