bug#64185: proposal for new function: copy-line

[Eli Zaretskii]

> From: Mattias Engdegård <mattias.engdegard@gmail.com>
> Date: Fri, 30 Jun 2023 19:13:26 +0200
> Cc: Eli Zaretskii <eliz@gnu.org>,
>  64185@debbugs.gnu.org,
>  me@eshelyaron.com,
>  zkanfer@gmail.com
> 
> 29 juni 2023 kl. 09.13 skrev Juri Linkov <juri@linkov.net>:
> 
> > I don't know if this can be closed now, since a new option for
> > duplicate-dwim could be created here as well.
> 
> Indeed, and here it is. It also fixes a bug when duplicating some rectangles, 
> which arose from changes in Emacs 29.
> 
> There is only a single variable for both contiguous and rectangular regions; 
> maybe we should have them separate -- not sure.
> 
> Since this is intended for emacs-29, I'm posting it here for approval first.

Sorry, this is too much for emacs-29.  Please either find a simpler
change for Emacs 29, or install on master.