Fix help options ensuring the --all argument is printed

[phillipj]

I small fix where a ; resulted in the last line of the help text didn't get printed.

Before

$ flow-node -h
Usage: flow-node [options] [ script.js ] [arguments]

Options:
  -h, --help            Show this message
  -v, --version         Prints the current version of flow-node
  -e, --eval script     Evaluate script
  -p, --print script    Evaluate script and print result
  -c, --check           Syntax check script without executing

After

$ flow-node -h
Usage: flow-node [options] [ script.js ] [arguments]

Options:
  -h, --help            Show this message
  -v, --version         Prints the current version of flow-node
  -e, --eval script     Evaluate script
  -p, --print script    Evaluate script and print result
  -c, --check           Syntax check script without executing
  -a, --all             Interpret all files as flow-typed, not just those with a @flow comment

[leebyron]

Thanks!