Remove Widget::afterRender()

After some discussion, none of us could come up for a reason for it to
stick around.

src/View/Helper/FormHelper.php

@@ -2275,11 +2275,7 @@ public function widget($name, array $data = []) {
 		}
 		unset($data['secure']);
 
-		$out = $widget->render($data);
-		if (method_exists($widget, 'afterRender')) {
-			$widget->afterRender($this->_View, $data);
-		}
-		return $out;
+		return $widget->render($data);
 	}
 
 /**