bug#20164: 25.0.50; Do not tell users that `x-show-tip' is internal

[Drew Adams <drew.adams@oracle.com>]

The doc string says this:

  This is an internal function; Lisp code should call `tooltip-show'.

Why?  While it is true that you can get, using `tooltip-show', the
behavior of arg PARMS by binding `tooltip-frame-parameters', the behavior
of args DX and DY by binding `tooltip-x-offset' and `tooltip-y-offset',
and the behavior of arg TIMEOUT by binding `tooltip-hide-delay' (which is
not documented, BTW), you cannot the behavior of arg FRAME.  And binding
user options is not really a great way to control the function behavior,
in general.

So `tooltip-show' is not really a user-level substitute for "internal"
`x-tooltip-show'.

What's more, the doc of `tooltip-show' explicitly refers to how variable
`x-max-tooltip-size' affects the behavior.  Why refer to that "internal"
variable?  And if it is not "internal" then why does it have the prefix
`x-'?  Why isn't there a `tooltip-max-size' option, corresponding to the
other `tooltip-*' options?

It looks like this design/implementation is incomplete.  It is great to
have `tooltip-mode' and `tooltip-show'.  But we should not be telling
users to use only `tooltip-show' and not `x-show-tip'.  I see no reason
for that.  The two functions are different; that's all.  Neither should
be considered more "internal" than the other.


In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2014-10-20 on LEG570
Bzr revision: 118168 rgm@gnu.org-20141020195941-icp42t8ttcnud09g
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking=yes,glyphs CPPFLAGS=-DGLYPH_DEBUG=1'