message: directly map partial_cmp in reverse
diff: @@ -480,7 +480,7 @@ macro_rules! impl_partialord_rev {
  impl PartialOrd<$typ> for $scalar {
  #[inline]
  fn partial_cmp(&self, other: &$typ) -> Option<Ordering> {
  - other.partial_cmp(self).map(|o| o.reverse())
  + other.partial_cmp(self).map(Ordering::reverse)
  }
  }
  };
  