bug#43519: 28.0.50; Overlay at end of minibuf hides minibuf's real content

[Gregory Heytings]

Hi Stefan,

> > IOW, you leave it entirely to the generic window-display code to select 
> > window-start based just on the value of point?
>
> Yes.  It seems to work very well. Even the corner case regression above 
> doesn't seem very serious and can be addressed using the 
> scroll_conservatively code.

I tried your patch, and it works very well indeed.  It seems that it's a 
much deeper change to the code than what I suggested, which would have 
given the same effect but only upon request.  Of course I'm fine with this 
too.