Apply suggestions from code review

Co-authored-by: Günther Foidl <[email protected]>

Author: Poker-sang

Diff for: src/ImageSharp/Formats/Ani/AniDecoderCore.cs

@@ -21,7 +21,7 @@ namespace SixLabors.ImageSharp.Formats.Ani;
 
 internal class AniDecoderCore(DecoderOptions options) : ImageDecoderCore(options)
 {
-    private enum ListIconChunkType
+    private enum ListIconChunkType : byte
     {
         Ico = 1,
         Cur = 2,

Diff for: src/ImageSharp/Formats/Ani/AniHeader.cs

@@ -28,7 +28,7 @@ internal readonly struct AniHeader
 
     public static ref AniHeader Parse(ReadOnlySpan<byte> data) => ref Unsafe.As<byte, AniHeader>(ref MemoryMarshal.GetReference(data));
 
-    public void WriteTo(in Stream stream) => stream.Write(MemoryMarshal.AsBytes(MemoryMarshal.CreateReadOnlySpan(in this, 1)));
+    public void WriteTo(Stream stream) => stream.Write(MemoryMarshal.AsBytes(MemoryMarshal.CreateReadOnlySpan(in this, 1)));
 }
 
 /// <summary>