Add example of bind readline-command-line

[Dan Jacobson]

bash man page says
              -v     Display  readline variable names and values in such a way
                     that they can be re-read.
Perhaps add an example of rereading via the bind command:
$ bind 'set bell-style visible'
else the user might try:
$ echo set bell-style visible|bind
Yes, we see
bind readline-command-line
well maybe say
bind 'readline-command-line'