chore: make XamlScope a readonly record struct

src/Uno.UI/UI/Xaml/XamlScope.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Text;
+using System.Collections.Immutable;
 using Uno.UI.DataBinding;
 
 namespace Microsoft.UI.Xaml
@@ -11,7 +8,7 @@ namespace Microsoft.UI.Xaml
 	/// opposed to the visual tree. In particular it allows correct resolution during template resolution, where the visual tree may be
 	/// arbitrarily distant from the xaml tree.
 	/// </summary>
-	internal record XamlScope(ImmutableStack<ManagedWeakReference> Sources)
+	internal readonly record struct XamlScope(ImmutableStack<ManagedWeakReference> Sources)
 	{
 		public XamlScope Push(ManagedWeakReference source)
 			=> new(Sources.Push(source));