message: updated golang signature example in doc comment
diff: // // handle the error
  // }
  //
  -// s := signature.NewSigner(kh)
  +// s, err := signature.NewSigner(kh)
  +// if err != nil {
  +// // handle error
  +// }
  //
  // a , err := s.Sign([]byte("this data needs to be signed"))
  // if err != nil {
  -// // handle error
  +// // handle the error
  +// }
  +//
  +// pubkh, err := kh.Public()
  +// if err != nil {
  +// // handle the error
  // }
  //
  -// v := signature.NewVerifier(kh)
  +// v, err := signature.NewVerifier(pubkh)
  +// if err != nil {
  +// // handle the error
  +// }
  //
  // if err := v.Verify(a, []byte("this data needs to be signed")); err != nil {
  -// // handle error
  +// // handle the error
  // }
  // }
  package signature
  