use initializer lists

Change-Id: I82b04601f1db52197b3dc625b6b7e0f143c1c8b6
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/scxmleditor/plugin_interface/graphicsscene.cpp

@@ -870,7 +870,7 @@ void GraphicsScene::highlightWarningItem(const ScxmlEditor::OutputPane::Warning
     ScxmlTag *tag = tagByWarning(w);
 
     if (tag)
-        highlightItems(QVector<ScxmlTag*>() << tag);
+        highlightItems({tag});
     else
         unhighlightAll();
 }