bug#7729: 24.0.50; doc string of `image-mode-fit-frame'

[Drew Adams]

Doc string:
 
"Fit the frame to the current image.
This function assumes the current frame has only one window."
 
But the command actually toggles between fitting the frame to the image
and restoring the previous frame size.  This behavior should be
mentioned in the doc.  Actually, the command name should reflect this
behavior: `toggle-fit-frame-to-image' or some such.
 

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2010-12-20 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4) --no-opt --cflags
-Ic:/imagesupport/include'