bug#81606: Mojibake with UTF-8 file names

> From: Arash Esbati <[email protected]>
> Cc: [email protected],  [email protected]
> Date: Sun, 16 Aug 2026 14:00:16 +0200
> 
> Werner LEMBERG <[email protected]> writes:
> 
> > Thanks.  I also suggest that the AUCTeX documentation mentions the
> > importance of the 'coding:' cookie for master file names with
> > non-ASCII characters.
> 
> I plan to install something like this.  Does it make sense to you?
> 
> --8<---------------cut here---------------start------------->8---
> diff --git a/doc/auctex.texi b/doc/auctex.texi
> index 07ad346c..16e6e228 100644
> --- a/doc/auctex.texi
> +++ b/doc/auctex.texi
> @@ -4717,6 +4717,17 @@ your files.
>  %%% End:
>  @end example
> 
> +If you're using non-ASCII characters in the name of the master file and
> +Emacs doesn't detect the master file correctly, you should give Emacs a
> +hint about the correct coding of the current file like this:
> +
> +@example
> +%%% Local Variables:
> +%%% coding: utf-8
> +%%% TeX-master: "ä-master"
> +%%% End:
> +@end example
> +

I suggest to remove the second part of the condition: the 'coding:'
cookie is recommended whenever the main file has non-ASCII characters
in its name, regardless of whether Emacs can or cannot detect the
encoding.