LibGfx: Remove 'QOIImageDecoderPlugin: ' prefix from error messages

What the component which did the actual decoding is called is not
relevant for the error, and would be rather distracting once we show
decoding error messages e.g. in ImageViewer (instead of just silently
failing).
Also makes them more consistent as many already don't include it - a
mistake which is now turned into a feature :^)

Userland/Libraries/LibGfx/QOILoader.cpp

@@ -26,9 +26,9 @@ static ErrorOr<QOIHeader> decode_qoi_header(InputMemoryStream& stream)
     QOIHeader header;
     stream >> Bytes { &header, sizeof(header) };
     if (stream.handle_any_error())
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: end of stream while reading header"sv);
+        return Error::from_string_literal("Invalid QOI image: end of stream while reading header"sv);
     if (StringView { header.magic, array_size(header.magic) } != QOI_MAGIC)
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: incorrect header magic"sv);
+        return Error::from_string_literal("Invalid QOI image: incorrect header magic"sv);
     header.width = AK::convert_between_host_and_big_endian(header.width);
     header.height = AK::convert_between_host_and_big_endian(header.height);
     return header;
@@ -112,7 +112,7 @@ static ErrorOr<u8> decode_qoi_op_run(InputMemoryStream& stream)
     u8 byte;
     stream >> byte;
     if (stream.handle_any_error())
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: end of stream while reading QOI_OP_RUN chunk"sv);
+        return Error::from_string_literal("Invalid QOI image: end of stream while reading QOI_OP_RUN chunk"sv);
     VERIFY((byte & QOI_MASK_2) == QOI_OP_RUN);
     u8 run = byte & ~QOI_MASK_2;
 
@@ -121,7 +121,7 @@ static ErrorOr<u8> decode_qoi_op_run(InputMemoryStream& stream)
 
     // Note that the run-lengths 63 and 64 (b111110 and b111111) are illegal as they are occupied by the QOI_OP_RGB and QOI_OP_RGBA tags.
     if (run == QOI_OP_RGB || run == QOI_OP_RGBA)
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: illegal run length"sv);
+        return Error::from_string_literal("Invalid QOI image: illegal run length"sv);
 
     VERIFY(run >= 1 && run <= 62);
     return run;
@@ -132,11 +132,11 @@ static ErrorOr<void> decode_qoi_end_marker(InputMemoryStream& stream)
     u8 bytes[array_size(END_MARKER)];
     stream >> Bytes { &bytes, array_size(bytes) };
     if (stream.handle_any_error())
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: end of stream while reading end marker"sv);
+        return Error::from_string_literal("Invalid QOI image: end of stream while reading end marker"sv);
     if (!stream.eof())
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: expected end of stream but more bytes are available"sv);
+        return Error::from_string_literal("Invalid QOI image: expected end of stream but more bytes are available"sv);
     if (memcmp(&END_MARKER, &bytes, array_size(bytes)) != 0)
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: incorrect end marker"sv);
+        return Error::from_string_literal("Invalid QOI image: incorrect end marker"sv);
     return {};
 }
 
@@ -144,9 +144,9 @@ static ErrorOr<NonnullRefPtr<Bitmap>> decode_qoi_image(InputMemoryStream& stream
 {
     // FIXME: Why is Gfx::Bitmap's size signed? Makes no sense whatsoever.
     if (width > NumericLimits<int>::max())
-        return Error::from_string_literal("QOIImageDecoderPlugin: Cannot create bitmap for QOI image of valid size, width exceeds maximum Gfx::Bitmap width"sv);
+        return Error::from_string_literal("Cannot create bitmap for QOI image of valid size, width exceeds maximum Gfx::Bitmap width"sv);
     if (height > NumericLimits<int>::max())
-        return Error::from_string_literal("QOIImageDecoderPlugin: Cannot create bitmap for QOI image of valid size, height exceeds maximum Gfx::Bitmap height"sv);
+        return Error::from_string_literal("Cannot create bitmap for QOI image of valid size, height exceeds maximum Gfx::Bitmap height"sv);
 
     auto bitmap = TRY(Bitmap::try_create(BitmapFormat::BGRA8888, { width, height }));
 
@@ -161,7 +161,7 @@ static ErrorOr<NonnullRefPtr<Bitmap>> decode_qoi_image(InputMemoryStream& stream
             if (run == 0) {
                 u8 tag = stream.peek_or_error();
                 if (stream.handle_any_error())
-                    return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: end of stream while reading chunk tag"sv);
+                    return Error::from_string_literal("Invalid QOI image: end of stream while reading chunk tag"sv);
                 if (tag == QOI_OP_RGB)
                     pixel = TRY(decode_qoi_op_rgb(stream));
                 else if (tag == QOI_OP_RGBA)
@@ -175,7 +175,7 @@ static ErrorOr<NonnullRefPtr<Bitmap>> decode_qoi_image(InputMemoryStream& stream
                 else if ((tag & QOI_MASK_2) == QOI_OP_RUN)
                     run = TRY(decode_qoi_op_run(stream));
                 else
-                    return Error::from_string_literal("QOIImageDecoderPlugin: Invalid QOI image: unknown chunk tag"sv);
+                    return Error::from_string_literal("Invalid QOI image: unknown chunk tag"sv);
             }
             auto index_position = (pixel.red() * 3 + pixel.green() * 5 + pixel.blue() * 7 + pixel.alpha() * 11) % 64;
             previous_pixels[index_position] = pixel;
@@ -230,7 +230,7 @@ bool QOIImageDecoderPlugin::sniff()
 ErrorOr<ImageFrameDescriptor> QOIImageDecoderPlugin::frame(size_t index)
 {
     if (index > 0)
-        return Error::from_string_literal("QOIImageDecoderPlugin: Invalid frame index"sv);
+        return Error::from_string_literal("Invalid frame index"sv);
 
     if (m_context->state == QOILoadingContext::State::NotDecoded) {
         InputMemoryStream stream { { m_context->data, m_context->data_size } };