Called automatically to inform the window that it is no longer the key window.
- iOS 2.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
Never call this method directly. The system calls this method and posts
did to let the window know when it is no longer key. The default implementation of this method does nothing, but subclasses can override it and use it to perform tasks related to resigning the key window status.