bug#12144: 24.1; (elisp) `Initial Parameters' misleading about minibuffer-only

In this node, the text tries to say that if `initial-frame-alist'
contains (minbuffer), i.e., (minibuffer . nil) then that means that you
also want to create another, minibuffer-only frame, which has the
parameter value (minbuffer . only).  And so Emacs creates that
standalone minibuffer frame for you automatically.

The existing text that tries to say this is highly misleading.  It
actually suggests that (minibuffer . nil) specifies a separate
minibuffer-only frame, whereas it is (minibuffer . only) that specifies
that.

IOW, it tries to do too much in a single sentence.  What it should say
is that (minibuffer . nil) means that the initial frame has NO
minibuffer.  And that if you do that then Emacs assumes you want a
standalone minibuffer frame, so it creates one for you.

IOW, although creation of the standalone minibuffer frame is really
separate from creation of the initial frame, if the initial frame does
not have a minibuffer then Emacs creates two frames, the second being
minibuffer-only.

All that should be said is this:

"If `initial-frame-alist' contains (minibuffer . nil) then Emacs creates
not only an initial frame, with no minibuffer, but also a separate,
minibuffer-only frame."

In GNU Emacs 24.1.1 (i386-mingw-nt5.1.2600)
 of 2012-06-10 on MARVIN
Windowing system distributor `Microsoft Corp.', version 5.1.2600