On Mac OS X the no differences informational message was linewrapped
at the wrong points due to the limited width of the system dialog,
yet the LFs embedded in the message (where I linewrapped it manually)
were also being honored. This resulted in a very difficult to read
paragraph of text.
So this narrows the text down by another 10 columns or so, making it
more readable.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>