bug#59094: 29.0.50; ediff-revision flags wrong lines in etc/HELLO

[Eli Zaretskii <eliz@gnu.org>]

> From: Mike Kupfer <mkupfer@alum.berkeley.edu>
> Date: Sun, 06 Nov 2022 21:29:06 -0800
> 
> From the top level directory of the git repository, running "emacs -Q":
> 
> 1. C-c C-f etc/HELLO RET
> 
> 2. M-x ediff-revision RET HELLO RET 0df73dabc16 RET 8721e87a6ec RET
> 
> Ediff says there are 6 diffs.  When I move through the diffs (e.g., by
> typing SPC in the Ediff control buffer), the first 4 claim that a line
> has been added, but that line already exists in the old revision (see
> attached screenshot).  These are the lines for Batak, Efik, Hanifi
> Rohingya, and Rejang.
> 
> Furthermore, ediff does not flag lines that actually are new: Adlam,
> Coptic, Gothic, Mende Kikakui, and Wancho.  Nor does it catch the change
> to Ukrainian.

I don't think Ediff can cope with portions of the file that disappear
from buffer text.  All the annotations that enriched.el eats up when
decoding the file are visible to Diff, and they get in the way of
counting characters.

Note that the real diffs also have 6 changes, just not where Ediff
shows them.