argument name with `_` underscore is misaligned to `-` hyphen

[rbuckland]

argument name with `_` underscore is misaligned to `-` hyphen

[rbuckland]

Here is the cause -

docopt.rs/src/dopt.rs

Line 491 in 62cf32b

name.replace("_", "-")

and the workaround is to "change" docopt arguments (variables) to be - hyphened versions

eg:

Usage:
  bar <foo-path>

instead of

Usage:
  bar <foo_path>

#[macro_use]
extern crate serde_derive;
extern crate docopt;

use docopt::Docopt;

const USAGE: &'static str = "
JSON XPather

Usage:
  bar <foo-path>

";

#[derive(Debug, Deserialize)]
struct Args {
    arg_foo_path: String,
}


fn main() {
    let args: Args = Docopt::new(USAGE)
                            .and_then(|d| d.deserialize())
                            .unwrap_or_else(|e| e.exit());
    println!("{:?}", args);
}