message: Note that token can be read from stdin
diff: @@ -21,7 +21,7 @@ pub struct Options {
  }
  pub const USAGE: &'static str = "
  -Save an api token from the registry locally
  +Save an api token from the registry locally. If token is not specified, it will be read from stdin.
  Usage:
  cargo login [options] [<token>]
  