bug#50323: 27.2; dired-do-touch documentation improvement

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Date: Thu, 02 Sep 2021 18:52:52 +0300
> Cc: joshua@joshuao.com, 50323@debbugs.gnu.org
> 
> >> "Touch the specified files (dired-do-touch). This means updating their
> >> modification times to /timestamp/. This is like the shell command
> >> touch."
> >
> > Thanks; now updated to this in Emacs 28.
> 
> It seems the original text tried to say that dired-do-touch
> defaults to the present time when RET is typed in the minibuffer,
> and indeed it prompt says " (default now): ".

Thanks, fixed.