bug#74090: 31.0.50; Problems with dabbrev-expand

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 29 Oct 2024 18:06:18 +0100
> From:  Stephen Berman via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> >From my debugging of these problems, I think they arise because the code
> in dabbrev-expand that sets up looking for an expansion (either
> directly, or after a space, or as a replacement for the current
> expansion) wrongly using positions in the buffer from which
> dabbrev-expand was invoked instead of the buffer in which the expansion
> is found.  The attached patch fixes these problems, according to my
> tests.  The patch includes comments justifying or at least motivating
> the changes.

Thanks, feel free to install on the emacs-30 branch.

> +                 ;; Comparing with point only makes sense in the buffer
> +                 ;; where we called dabbrev-exand, but if that differs
                                       ^^^^^^^^^^^^^
Typo.