bug#29805: 27.0; doc of `tooltip-resize-echo-area'

[martin rudalics <rudalics@gmx.at>]

 > In any case, it seems to have no effect, AFAICT, on a standalone
 > minibuffer frame (i.e., on an echo area in such a frame).  The doc says
 > nothing about this..

I believe we also nowhere say that we do not resize minibuffer/echo
areas on stand-alone minibuffer frames.  So the question to be
answered first is: Do we ever want to fit stand-alone minibuffer
frames to their buffers?  If so, then we can decide whether we want
`tooltip-resize-echo-area' to affect resizing stand-alone minibuffer
frames as well and probably also whether showing a tooltip should
autoraise the minibuffer frame.

But the first question that comes to my mind is why we now have the
option `tooltip-resize-echo-area' which, according to its doc-string
"has effect only on GUI frames" while in Emacs 24.1 we have declared
`tooltip-use-echo-area' obsolete and suggested to disable tooltips
instead.  Resolved that, we should probably then also say that
`tooltip-resize-echo-area' has effect iff `resize-mini-windows' is
non-nil.

martin