bug#51132: Make sure user is doubly aware of finished complilations

[Eli Zaretskii]

> From: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
> Cc: 51132@debbugs.gnu.org
> Date: Tue, 12 Oct 2021 16:04:04 +0800
> 
> EZ>   . I see "Compilation:exit" on the mode line (all of them)
> 
> Well in emacs-version "27.1" the Compilation:exit is only in the
> *compilation* buffer's modeline. That's all I know.

Which is great, and you should see it.