feat: Implemented MarkupExtensionReturnTypeAttribute

Author: VitezslavImrysek

src/Uno.UI/Generated/3.0.0.0/Windows.UI.Xaml.Markup/MarkupExtensionReturnTypeAttribute.cs

@@ -2,20 +2,20 @@
 #pragma warning disable 114 // new keyword hiding
 namespace Windows.UI.Xaml.Markup
 {
-	#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+	#if false
 	[global::Uno.NotImplemented]
 	#endif
 	public  partial class MarkupExtensionReturnTypeAttribute : global::System.Attribute
 	{
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__WASM__", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
 		public MarkupExtensionReturnTypeAttribute() : base()
 		{
 			global::Windows.Foundation.Metadata.ApiInformation.TryRaiseNotImplemented("Windows.UI.Xaml.Markup.MarkupExtensionReturnTypeAttribute", "MarkupExtensionReturnTypeAttribute.MarkupExtensionReturnTypeAttribute()");
 		}
 		#endif
 		// Forced skipping of method Windows.UI.Xaml.Markup.MarkupExtensionReturnTypeAttribute.MarkupExtensionReturnTypeAttribute()
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		public  global::System.Type ReturnType;
 		#endif
 	}

src/Uno.UI/Microsoft/UI/Xaml/Markup/MarkupExtensionReturnTypeAttribute.cs

@@ -0,0 +1,16 @@
+using System;
+using Windows.Foundation.Metadata;
+
+namespace Windows.UI.Xaml.Markup
+{
+	[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
+	[WebHostHidden]
+	public sealed partial class MarkupExtensionReturnTypeAttribute : Attribute
+	{
+		public MarkupExtensionReturnTypeAttribute()
+		{
+		}
+
+		public Type ReturnType;
+	}
+}