[PT Settings] Rename "Microsoft.PowerToys.Setting.UI.Runner" to "PowerToys.Settings" (#9637)

src/settings-ui/PowerToys.Settings/App.xaml.cs

@@ -0,0 +1,15 @@
+// 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 System.Windows;
+
+namespace PowerToys.Settings
+{
+    /// <summary>
+    /// Interaction logic for App.xaml.
+    /// </summary>
+    public partial class App : Application
+    {
+    }
+}