message: fix typo in dev help text
diff: @@ -432,7 +432,7 @@ fn run() -> Result<(), failure::Error> {
  )
  .arg(
  Arg::with_name("ip")
  - .help("ip to listsen on. defaults to localhost")
  + .help("ip to listen on. defaults to localhost")
  .short("i")
  .long("ip")
  .takes_value(true)
  