message: Resolve an internal capitalization inconsistency
diff: @@ -108,8 +108,8 @@ pub struct IcoDecoder<R: Read> {
  }
  enum InnerDecoder<R: Read> {
  - BMP(BmpDecoder<R>),
  - PNG(PngDecoder<R>),
  + Bmp(BmpDecoder<R>),
  + Png(PngDecoder<R>),
  }
  #[derive(Clone, Copy, Default)]
  @@ -248,9 +248,9 @@ impl DirEntry {
  self.seek_to_start(&mut r)?;
  if is_png {
  - Ok(PNG(PngDecoder::new(r)?))
  + Ok(Png(PngDecoder::new(r)?))
  } else {
  - Ok(BMP(BmpDecoder::new_with_ico_format(r)?))
  + Ok(Bmp(BmpDecoder::new_with_ico_format(r)?))
  }
  }
  }
  @@ -276,15 +276,15 @@ impl<'a, R: 'a + Read + Seek> ImageDecoder<'a> for IcoDecoder<R> {
  fn dimensions(&self) -> (u32, u32) {
  match self.inner_decoder {
  - BMP(ref decoder) => decoder.dimensions(),
  - PNG(ref decoder) => decoder.dimensions(),
  + Bmp(ref decoder) => decoder.dimensions(),
  + Png(ref decoder) => decoder.dimensions(),
  }
  }
  fn color_type(&self) -> ColorType {
  match self.inner_decoder {
  - BMP(ref decoder) => decoder.color_type(),
  - PNG(ref decoder) => decoder.color_type(),
  + Bmp(ref decoder) => decoder.color_type(),
  + Png(ref decoder) => decoder.color_type(),
  }
  }
  @@ -295,7 +295,7 @@ impl<'a, R: 'a + Read + Seek> ImageDecoder<'a> for IcoDecoder<R> {
  fn read_image(self, buf: &mut [u8]) -> ImageResult<()> {
  assert_eq!(u64::try_from(buf.len()), Ok(self.total_bytes()));
  match self.inner_decoder {
  - PNG(decoder) => {
  + Png(decoder) => {
  if self.selected_entry.image_length < PNG_SIGNATURE.len() as u32 {
  return Err(DecoderError::PngShorterThanHeader.into());
  }
  @@ -318,7 +318,7 @@ impl<'a, R: 'a + Read + Seek> ImageDecoder<'a> for IcoDecoder<R> {
  decoder.read_image(buf)
  }
  - BMP(mut decoder) => {
  + Bmp(mut decoder) => {
  let (width, height) = decoder.dimensions();
  if !self.selected_entry.matches_dimensions(width, height) {
  return Err(DecoderError::ImageEntryDimensionMismatch {
  