bug#61069: 30.0.50; comint-copy-old-input should include continuation lines

[Eli Zaretskii]

> From: Bob Rogers <rogers@rgrjr.com>
> Date: Thu, 26 Jan 2023 00:38:56 -0800
> CC: 61069@debbugs.gnu.org
> 
>    Oh, you mean the backslashes that come from the Makefile itself, like
>    the one after "=pdump"?
> 
> Exactly.
> 
>    > My thought is that C-RET on the "./temacs -batch" line in a *shell*
>    > buffer should take both that line and the next.
> 
>    That has to be an optional feature, probably off by default.
> 
> As you like.  Should this be a comint thing, or a shell thing?

The latter, I think.  Comint handles clients that don't necessarily
use the backslash convention for continuing lines.