Fix ordering

src/ImageSharp/PixelFormats/PixelBlender{TPixel}.cs

@@ -1,10 +1,10 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-using SixLabors.ImageSharp.Memory;
 using System;
 using System.Buffers;
 using System.Numerics;
+using SixLabors.ImageSharp.Memory;
 
 namespace SixLabors.ImageSharp.PixelFormats
 {