bug#65094: 30.0.50; '/ u' is missing in menu bar under Package

[Eli Zaretskii]

> From: Arash Esbati <arash@gnu.org>
> Cc: 65094@debbugs.gnu.org
> Date: Sat, 05 Aug 2023 17:46:05 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > No reason.  Feel free to submit a patch to add that, but please do it
> > for the emacs-29 branch (as I believe that command exists in Emacs 29
> > as well).
> 
> Yes, that command was introduced with Emacs 28.1, IIUC.  Please find
> attached a patch against the emacs-29 branch.

Thanks, but can we make the help-echo string a bit more helpful, by
not just repeating what the item's name says?  What does it mean "by
upgradeability" -- does it mean only packages that can be upgraded
will be shown? if so, let's say so.

(Yes, I know the other help-echo are also of this kind, but that
doesn't mean they are a good example to follow...)