Revert breaking change

Author: JimBobSquarePants

src/ImageSharp/Formats/Webp/WebpBlendMethod.cs

@@ -8,15 +8,15 @@ namespace SixLabors.ImageSharp.Formats.Webp;
 /// </summary>
 public enum WebpBlendMethod
 {
-    /// <summary>
-    /// Do not blend. After disposing of the previous frame,
-    /// render the current frame on the canvas by overwriting the rectangle covered by the current frame.
-    /// </summary>
-    Source = 1,
-
     /// <summary>
     /// Use alpha blending. After disposing of the previous frame, render the current frame on the canvas using alpha-blending.
     /// If the current frame does not have an alpha channel, assume alpha value of 255, effectively replacing the rectangle.
     /// </summary>
     Over = 0,
+
+    /// <summary>
+    /// Do not blend. After disposing of the previous frame,
+    /// render the current frame on the canvas by overwriting the rectangle covered by the current frame.
+    /// </summary>
+    Source = 1,
 }