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

[Drew Adams]

> > Users can easily control the duration of this
> > "flash", as well as its color.  And they can
> > control what text, if any, is shown at the right
> > edge of the area.  The default text is musical
> > note chars.
> 
> BTW, this aquamarine looks a bit nicer than the yellow flash in
> Gregory's version, and I like that it's implemented solely in Elisp.
> 
> (https://urldefense.com/v3/__https://www.emacswiki.org/emacs/echo-
> bell.el__;!!GqivPVa7Brio!NXvNy4ePYJu7-yFxNANdGuqcHj0K8fXxFMLl-
> Y720teI23EXPdOS6nALvnt_cBpq$ )
> 
> Still not sure if that is the behavior we want to provide OOTB (no Atom
> or VSCode-level of "slickness" in there), but why not ask people.

For whatever you guys decide to do:

. There's the question of the default behavior.

. And there's the question of how easy it is for
  users to modify the behavior in different ways.