bug#27479: Buffer text not repainted after `insert'

[npostavs]

> From: John Beck <john.morris.beck@gmail.com>
> Subject: Re: bug#27479:
> To: npostavs@users.sourceforge.net, 27479@debbugs.gnu.org
> Date: Sun, 25 Jun 2017 10:19:43 -0700 (49 minutes, 40 seconds ago)
>
> I would say that is a *huge* wat.
>
> For now I have resolved to use this:
>
> (sequential-insert (arg) (progn (insert arg) (redisplay)))
>
> This avoids backwards compatibility issues and and allows the user to be
> explicit about whether or not they are inserting "sequentially."
>
> I feel that something along the lines of this sequential-insert should be
> included in mainline emacs though that is entirely your call.

Apart from simulating a human typing I don't see a need for this
function.  It could go in lisp/play/animation.el perhaps.  Did you have
some other use case in mind?

By the way, `sit-for' triggers redisplay, so you might want to use that
instead of `sleep-for'.