Partial compile fix for current Qt dev and/or Qt 6

This does not cover Utils::MapReduceOption with QVector, and code
that's not compiled on my machine.

Change-Id: Ib63923985c52b1bb74e5ec2068a2bb37469ac618
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/qmljseditor/qmljshoverhandler.h

@@ -32,10 +32,6 @@
 #include <QColor>
 #include <QCoreApplication>
 
-QT_BEGIN_NAMESPACE
-template <class> class QList;
-QT_END_NAMESPACE
-
 namespace QmlJS {
 class ScopeChain;
 class Context;