bug#42811: 26.1; visual-line-mode wraps at no-break space

[Eli Zaretskii <eliz@gnu.org>]

> From: Marvin ‘quintus’ Gülker
>  <post+ebugs@guelker.eu>
> Cc: 42811@debbugs.gnu.org
> Date: Wed, 12 Aug 2020 07:59:06 +0200
> 
> Am Dienstag, dem 11. August 2020 schrieb Eli Zaretskii:
> > If you set nobreak-char-display to nil, you get the behavior you want.
> 
> Indeed, this works. But now the NBSP is not highlighted anymore as a
> special character and I won't notice it is in there. Is there a way to
> have both the highlighted display and the no-break behaviour?

I made such a change (on the master branch), not without some
trepidation, as the current behavior is very old (15 years), so I
wonder whether some feature relies on that.  We shall see, I guess.

Note that when nobreak-char-display is non-nil and non-t, we still
produce an ASCII space after the backslash-escape, so the display
engine will still wrap at that spot.  But here, I cannot make the same
change, because the Emacs manual clearly documents this behavior.

Thanks.