Implemented UIViewController nextResponder

Change-Id: I39ed34eef0902760412af2176701a75c6d5f0251

src/frameworks/uikit/ui_view_controller.rs

@@ -184,6 +184,18 @@ pub const CLASSES: ClassExports = objc_classes! {
     interface_orientation == UIInterfaceOrientationPortrait
 }
 
+// UIResponder implementation
+// From the Apple UIView docs regarding [UIResponder nextResponder]:
+// "UIViewController similarly implements the method
+// and returns its view’s superview."
+// https://developer.apple.com/documentation/uikit/uiresponder/next?language=objc
+- (id)nextResponder {
+    let view = msg![env; this view];
+    let next_responder = msg![env; view superview];
+    log_dbg!("[(UIView*){:?} nextResponder] => {:?}", this, next_responder);
+    next_responder
+}
+
 @end
 
 };