Use typed syntax in calls to QMetaObject::invokeMethod

We do it wherever possible. Some places can't be fixed
since they still rely on dynamic introspection
(mainly QQuickItem cases).

Change-Id: Ia00b4a04d8b995c9a43b7bf2dbe76a60364bb8ca
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/cpptools/stringtable.cpp

@@ -108,7 +108,8 @@ QString StringTablePrivate::insert(const QString &string)
 
 void StringTable::scheduleGC()
 {
-    QMetaObject::invokeMethod(&m_instance->m_gcCountDown, "start", Qt::QueuedConnection);
+    QMetaObject::invokeMethod(&m_instance->m_gcCountDown, QOverload<>::of(&QTimer::start),
+                              Qt::QueuedConnection);
 }
 
 StringTable::StringTable()