Upate rgb test format

tests/ImageSharp.Tests/Colorspaces/RgbTests.cs

@@ -8,7 +8,6 @@ using Xunit;
 
 namespace SixLabors.ImageSharp.Tests.Colorspaces
 {
-
     /// <summary>
     /// Tests the <see cref="Rgb"/> struct.
     /// </summary>
@@ -48,9 +47,7 @@ namespace SixLabors.ImageSharp.Tests.Colorspaces
             const byte g = 128;
             const byte b = 255;
 
-            var rgb = new Rgb(r / 255F, g / 255F, b / 255F);
-
-            Rgb24 rgb24 = rgb;
+            Rgb24 rgb24 = new Rgb(r / 255F, g / 255F, b / 255F);
             Rgb rgb2 = rgb24;
 
             Assert.Equal(r, rgb24.R);
@@ -69,9 +66,7 @@ namespace SixLabors.ImageSharp.Tests.Colorspaces
             const byte g = 128;
             const byte b = 255;
 
-            var rgb = new Rgb(r / 255F, g / 255F, b / 255F);
-
-            Rgba32 rgba32 = rgb;
+            Rgba32 rgba32 = new Rgb(r / 255F, g / 255F, b / 255F);
             Rgb rgb2 = rgba32;
 
             Assert.Equal(r, rgba32.R);