LibGfx/JBIG2: Replace an accidentally-committed XXX with a FIXME

No behavior change.

Author: nico

Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp

@@ -1910,6 +1910,7 @@ static ErrorOr<Vector<BilevelSubImage>> symbol_dictionary_decoding_procedure(Sym
             //     Decode the bitmap by reading this many bytes and treating it as HCHEIGHT rows of TOTWIDTH pixels, each
             //     row padded out to a byte boundary with 0-7 0 bits."
             if (bitmap_size == 0) {
+                // FIXME: Validate that the pad bits are 0.
                 auto result = TRY(BilevelImage::create(total_width, height));
                 TRY(bit_stream->read_until_filled(result->bytes()));
                 return result;

Userland/Libraries/LibGfx/ImageFormats/JBIG2Writer.cpp

@@ -1116,7 +1116,7 @@ static ErrorOr<ByteBuffer> symbol_dictionary_encoding_procedure(SymbolDictionary
             //
             //     Decode the bitmap by reading this many bytes and treating it as HCHEIGHT rows of TOTWIDTH pixels, each
             //     row padded out to a byte boundary with 0-7 0 bits."
-            TRY(bit_stream->write_until_depleted(image.bytes())); // XXX zero padding
+            TRY(bit_stream->write_until_depleted(image.bytes()));
 
             // "5) Skip over any bits remaining in the last byte read."
             TRY(bit_stream->align_to_byte_boundary());