[RFA/doco] Document the new default for "set print frame-arguments"

[Joel Brobecker]

> > 2009-04-02  Joel Brobecker  <brobecker@adacore.com>
> > 
> >         * gdb.texinfo (Backtrace): Add a parameter in frame 1 of the first
> >         example, and add a small explanation about it.
> >         (Print Settings): Change the documentation of the "set print
> >         frame-arguments" to reflect the fact that the default is now "scalars".
> OK.

Thank you. Committed.

-- 
Joel