Debugger: Use some Tr::tr in WatchModel related classes

Change-Id: I1fcd0c5f342da4fd5ff52c19eb9f3f20a9bdcc5b
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/debugger/watchhandler.h

@@ -56,13 +56,13 @@ signals:
     void updateFinished();
 };
 
-class WatchHandler : public QObject
+class WatchHandler
 {
-    Q_OBJECT
+    Q_DISABLE_COPY_MOVE(WatchHandler)
 
 public:
     explicit WatchHandler(DebuggerEngine *engine);
-    ~WatchHandler() override;
+    ~WatchHandler();
 
     WatchModelBase *model() const;