Say something about the convenient `exit` method in the docs.
Say something about the convenient `exit` method in the docs.

birkenfeld/docopt.rs,birkenfeld/docopt.rs,brandonson/docopt.rs,birkenfeld/docopt.rs,zsiciarz/docopt.rs,brandonson/docopt.rs,zsiciarz/docopt.rs,zsiciarz/docopt.rs,brandonson/docopt.rs