message: add display to hash
diff: @@ -158,6 +158,12 @@ impl From<hash::Blake2b256> for Hash {
  }
  }
  +impl std::fmt::Display for Hash {
  + fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
  + write!(f, "{}", self.0)
  + }
  +}
  +
  #[cfg(test)]
  mod test {
  use super::*;
  