bug#31194: 26.1; `display-buffer-in-major-side-window' was renamed without an alias.

[martin rudalics]

> I think that cases like this need to have NEWS entries under the
> "Incompatible Lisp Changes" section?  This was a function name which
> was not obviously internal (no double-hyphen), so one does tend to
> expect it to be documented if it no longer works (and the Changelog
> entry is not addressing this aspect).
>
> If the NEWS file mentioned the change and stated plainly that any
> libraries using the old name need to be updated, I think it would
> assist people who will run into this the way I did.

I've tried to do that now.  Please have a look.

Thanks, martin