bug#1305: All code that currently beeps should use visual bell instead

[Gregory Heytings]

> Fair enough. Still, it's more "proven" that yours, so to speak.

I don't know what you mean by "proven", but I never activated that visible 
bell before this discussion started, like Lars I just disabled the bell 
altogether.  And AFAICS this is also what most popular starter kits do. 
So at least to me it's not clear whether it is widely used.

> I don't mind putting it to the vote sometime, here or some other place.

I'd be very surprised if people voted for that, but indeed a vote is 
probably the best way to decide between the two.

> > Using inverse-video also creates extra colors, unless your frame 
> > happens to display only black on white or white on black elements on 
> > the first and last line.  Moreover with my patch the colors are fully 
> > configurable, so you can adapt them to your theme.
>
> It uses only the colors that are already there, though. Just in inverse.

Which means "new colors".  Of course from a logical viewpoint this is 
"just in inverse", but flashing a brown on white text in green on black, 
or a blue on white text in yellow on black, does create new colors that 
weren't there.  It's like photo negatives, the colors you see are not "the 
colors that were there".

> But it would be interesting to try some icon-based animation in the echo 
> area, like the red circle on VSCode's pic.

You mean, displaying such a red circle before the error message in the 
echo area?  Not sure that would be visible enough.