bug#44236: [PATCH] xdisp: Apply nobreak-char-display also to NARROW NO-BREAK SPACE U+202F

[Juri Linkov]

> IOW, we need to decide on the rationale for displaying these
> specially, and then we can decide which ones should have this applied.

For a long time my customization contained

  (setq dired-listing-switches "-Alv --block-size='1")

that in Dired buffers displays file sizes using nice space
as the thousands separator between groups of 3 digit.

But now this clean space between numbers is polluted by visual garbage
of unrequested highlighted underlines.

Using 'C-u C-x =' on the character shows that it's NARROW NO-BREAK SPACE
with the nobreak-space face on it.

The intention of nobreak-space is to warn the user about confusable
characters in writable buffers.  But why highlight such characters
in read-only Dired buffers?