chore: use file-scoped namespace

src/Shared/HandyControl_Shared/Interactivity/Commands/ShutdownAppCommand.cs

@@ -2,14 +2,13 @@
 using System.Windows;
 using System.Windows.Input;
 
-namespace HandyControl.Interactivity
+namespace HandyControl.Interactivity;
+
+public class ShutdownAppCommand : ICommand
 {
-    public class ShutdownAppCommand : ICommand
-    {
-        public bool CanExecute(object parameter) => true;
+    public bool CanExecute(object parameter) => true;
 
-        public void Execute(object parameter) => Application.Current.Shutdown();
+    public void Execute(object parameter) => Application.Current.Shutdown();
 
-        public event EventHandler CanExecuteChanged;
-    }
-}
+    public event EventHandler CanExecuteChanged;
+}