We previously only showed this message if the user had
`wait-after-command` set to true, since if its false the surface would
close anyways.
With the latest undo feature on macOS, this is no longer the case; a
exited process can be undone and reopened. I considered disallowing
undoing an exited surface, but I think there is value in being able to
go back and recapture output in scrollback if you wanted to.
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