message: Make `ErrFormatter` semi-private as well
diff: @@ -142,7 +142,7 @@ pub enum Error {
  /// An error formatter.
  #[derive(Clone, Copy, Debug)]
  -pub struct ErrFormatter<'a, T>(pub &'a T);
  +pub(crate) struct ErrFormatter<'a, T>(pub &'a T);
  impl<'a, T> Display for ErrFormatter<'a, T>
  where
  