message: Add comments explaining the DXGI constants
diff: @@ -243,10 +243,13 @@ impl<R: Read> DdsDecoder<R> {
  b"DXT5" => DxtVariant::DXT5,
  b"DX10" => {
  let dx10_header = DX10Header::from_reader(&mut r)?;
  + // Format equivalents were taken from https://docs.microsoft.com/en-us/windows/win32/direct3d11/texture-block-compression-in-direct3d-11
  + // The enum integer values were taken from https://docs.microsoft.com/en-us/windows/win32/api/dxgiformat/ne-dxgiformat-dxgi_format
  + // DXT1 represents the different BC1 variants, DTX3 represents the different BC2 variants and DTX5 represents the different BC3 variants
  match dx10_header.dxgi_format {
  - 70 | 71 | 72 => DxtVariant::DXT1,
  - 73 | 74 | 75 => DxtVariant::DXT3,
  - 76 | 77 | 78 => DxtVariant::DXT5,
  + 70 | 71 | 72 => DxtVariant::DXT1, // DXGI_FORMAT_BC1_TYPELESS, DXGI_FORMAT_BC1_UNORM or DXGI_FORMAT_BC1_UNORM_SRGB
  + 73 | 74 | 75 => DxtVariant::DXT3, // DXGI_FORMAT_BC2_TYPELESS, DXGI_FORMAT_BC2_UNORM or DXGI_FORMAT_BC2_UNORM_SRGB
  + 76 | 77 | 78 => DxtVariant::DXT5, // DXGI_FORMAT_BC3_TYPELESS, DXGI_FORMAT_BC3_UNORM or DXGI_FORMAT_BC3_UNORM_SRGB
  _ => {
  return Err(ImageError::Unsupported(
  UnsupportedError::from_format_and_kind(
  