Exiting nvim: If only register buffers remain on `:q`, close them all

[tuurep]

Constantly annoying when testing this plugin:

reg-quit.mp4

There's probably a simple buffer option for this, this issue is a reminder to look it up.

Reference: with :help splits, :q works exactly how I'd want these to work.

Edit: Oh, :help can only have one window open at a time. But if there could be many... you know what I mean

[nullromo]

Help can have multiple windows open.

1. vim -u NONE
2. :help 42
3. :sp
4. :help holy-grail

But I think perhaps the best way to do this is a WinClosed autocommand that checks if all the remaining windows/buffers are registereditor buffers. If they are, just quit vim entirely.