message: simplify error report to the cbor_event deserializer
diff: @@ -93,10 +93,7 @@ impl cbor_event::se::Serialize for Coin {
  impl cbor_event::de::Deserialize for Coin {
  fn deserialize<'a>(raw: &mut RawCbor<'a>) -> cbor_event::Result<Self> {
  Coin::new(raw.unsigned_integer()?).map_err(|err| {
  - match err {
  - Error::OutOfBound(v) => cbor_event::Error::CustomError(format!("coin ({}) out of bound, max: {}", v, MAX_COIN)),
  - Error::Negative => cbor_event::Error::CustomError("coin cannot hold negative value".to_owned()),
  - }
  + cbor_event::Error::CustomError(format!("{}", err))
  })
  }
  }
  