fix(Hyperlink): Add hyperlink foreground color for macOS

Author: kazo0

src/Uno.UI/UI/Xaml/Documents/Hyperlink.cs

@@ -22,7 +22,7 @@ private static Brush DefaultForeground
 			{
 				if (_defaultForeground == null)
 				{
-#if __IOS__ || __ANDROID__
+#if __IOS__ || __MACOS__ || __ANDROID__
 					_defaultForeground = GetDefaultForeground();
 #else
 					_defaultForeground = null;

src/Uno.UI/UI/Xaml/Documents/Hyperlink.macOS.cs

@@ -0,0 +1,19 @@
+#if __MACOS__
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Windows.UI.Xaml.Media;
+using Windows.UI;
+
+namespace Windows.UI.Xaml.Documents
+{
+	public partial class Hyperlink
+	{
+		private static Brush GetDefaultForeground()
+		{
+			// https://developer.apple.com/macos/human-interface-guidelines/visual-design/color/
+			return new SolidColorBrush(Color.FromArgb(255, 0, 122, 255));
+		}
+	}
+}
+#endif