add vi mode refresh command of inputrc to documentation

[Kevin Low]

I believe to be complete, you should add the vi mode refresh command of
inputrc to compliment the emacs refresh command you provided on the
following page:

http://www.gnu.org/software/bash/manual/bashref.html#Readline-Init-File-Syntax

8.3 Readline Init File

"In addition, the C-x C-r command re-reads this init file, thus
incorporating any changes that you might have made to it."

This refresh command you provided, won't work in VI mode.  It puts the
representation of CTRL-x (^x) on the command line, which I assume means it
wasn't interpreted as a command character.  CTRL-l, (el),  the redraw
screen command in VI does not cause bash to re-read its inputrc file
either.  Of course I would be interested to find out what the command is,
but more importantly, I think this information should be provided along
with the emacs information.

Thanks,
Kevin