Wrap the shortcut clear button with a warning

UWPHook/SettingsWindow.xaml.cs

@@ -85,9 +85,13 @@ namespace UWPHook
         }
 
         private void clearAll_button_Click(object sender, RoutedEventArgs e)
+        {
+            MessageBoxResult result = MessageBox.Show("This action will remove ALL shortcuts from non-Steam games." + Environment.NewLine + " Are you sure you want to continue?", "Warning", MessageBoxButton.YesNo, MessageBoxImage.Warning);
+            if (result == MessageBoxResult.Yes)
             {
                 GamesWindow.ClearAllShortcuts();
             }
+        }
 
         private void key_Button_Click(object sender, RoutedEventArgs e)
         {