pos-visible-in-window-p documentation

[Luc Teirlinck]

In revision 1.39 to lispref/windows.texi you changed the description
of `pos-visible-in-window-p' to say:

It returns `nil' if POSITION is scrolled vertically or horizontally
out of view.

Whereas the old documentation said that the function can return t if
POSITION is only out of view because of horizontal scrolling.
Checking it out empirically, it would appear that the _old_
documentation is correct.

The docstring says:

Return nil if that position is scrolled vertically out of view.

I believe that this particular part of revision 1.39 should be
reverted.  But am I missing something?

Sincerely,

Luc.