Utility for copying environments

[raingloom]

Tale as old as time: I was fed up with some software and instead of
patching it I created a workaround. But I think it could be genuinely
useful for some other folks too.
My main use case is gonna be opening new kakoune windows, but it should
be useful more generally as well.

https://git.sr.ht/~raingloom/with-env

Patches and feedback are welcome, as usual.

ps.: please forgive my typos. i really should not have stayed awake to
finish this.