Added onContentValidateData event.

Replaces `onUserBeforeDataValidation` event which is now deprecated.

libraries/src/MVC/Model/FormModel.php

@@ -192,7 +192,18 @@ public function validate($form, $data, $group = null)
 		// Include the plugins for the delete events.
 		PluginHelper::importPlugin($this->events_map['validate']);
 
-		Factory::getApplication()->triggerEvent('onUserBeforeDataValidation', array($form, &$data));
+		$dispatcher = Factory::getContainer()->get('dispatcher');
+
+		if (!empty($dispatcher->getListeners('onUserBeforeDataValidation'))) {
+		    @trigger_error(
+					'The `onUserBeforeDataValidation` event is deprecated and will be removed in 5.0, use the `onContentValidateData` event instead.',
+					E_USER_DEPRECATED
+				);
+
+		    Factory::getApplication()->triggerEvent('onUserBeforeDataValidation', array($form, &$data));
+		}
+
+		Factory::getApplication()->triggerEvent('onContentValidateData', array($form, &$data));
 
 		// Filter and validate the form data.
 		$data = $form->filter($data);