Use QListIterator in qt6

kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlenginepluginmanager.cpp

@@ -39,7 +39,11 @@ void ShortUrlEnginePluginManagerPrivate::initializePlugins()
 {
     const QVector<KPluginMetaData> plugins = KPluginMetaData::findPlugins(QStringLiteral("pimcommon/shorturlengine"));
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     QVectorIterator<KPluginMetaData> i(plugins);
+#else
+    QListIterator<KPluginMetaData> i(plugins);
+#endif
     i.toBack();
     while (i.hasPrevious()) {
         ShortUrlEnginePluginInfo info;