message: Exhaustively match in ColorType -> DynamicImage conversion
diff: @@ -1075,17 +1075,6 @@ fn decoder_to_image<'a, I: ImageDecoder<'a>>(decoder: I) -> ImageResult<DynamicI
  let buf = image::decoder_to_vec(decoder)?;
  ImageBuffer::from_raw(w, h, buf).map(DynamicImage::ImageLumaA16)
  }
  -
  - // An internal #[non_exhaustive]
  - #[allow(unreachable_patterns)]
  - _ => {
  - return Err(ImageError::Unsupported(
  - UnsupportedError::from_format_and_kind(
  - ImageFormatHint::Unknown,
  - UnsupportedErrorKind::Color(color_type.into()),
  - ),
  - ))
  - }
  };
  match image {
  