Specify the class used for the preferences for settings accessory. Must be a view controller.

Class to be presented when settings accessory is tapped; otherwise nil if settings accessory is not enabled. The class may conform to HSWidgetPreferences to directly apply changes to widget instance.

Since the class can be any view controller, we can benefit by using view controllers in the Preferences framework and plists similar to how tweak preferences are made. A few convenient preference view controller classes are provided for this.

Using a valid class will automatically enable the settings accessory.