message: Flag crate registry errors as "human"
  They often contain useful information!
  Closes
diff: @@ -71,7 +71,7 @@ impl CargoError {
  &CargoErrorKind::Curl(_) => true,
  &CargoErrorKind::HttpNot200(..) => true,
  &CargoErrorKind::ProcessErrorKind(_) => true,
  - &CargoErrorKind::CrateRegistry(_) |
  + &CargoErrorKind::CrateRegistry(_) => true,
  &CargoErrorKind::ParseSemver(_) |
  &CargoErrorKind::Semver(_) |
  &CargoErrorKind::Io(_) |
  