Settingsv2 fix warnings (#2076)

* updating a ton of warnings.

* bunch of cleanup

* few smaller ones

* fixed naming

* reversing an oops

* adjusting json to use attribute

* more json properties

src/core/Microsoft.PowerToys.Settings.UI/App.xaml.cs

@@ -1,4 +1,8 @@
-using Microsoft.Toolkit.Win32.UI.XamlHost;
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Toolkit.Win32.UI.XamlHost;
 
 namespace Microsoft.PowerToys.Settings.UI
 {