message: Fix unfinished note on AvifEncoder
diff: @@ -64,7 +64,8 @@ Image formats:
  - Reading lossless WebP is now supported.
  - The OpenEXR format is now supported.
  - The `jpeg` decoder has been upgraded to Lossless JPEG.
  -- The `AvifEncoder`
  +- The `AvifEncoder` now correctly handles alpha-less images. Some additional
  + color formats are converted to RGBA as well.
  - The `Bmp` codec now decodes more valid images. It can decode a raw image
  without performing the palette mapping. It provides a method to access the
  palette. The encoder provides the inverse capabilities.
  