Core: Use Qt5-style connects

The heavy lifting was done by clazy.

Change-Id: I2dde14919d917816d02117338205f8f861d8af0a
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/coreplugin/navigationwidget.h

@@ -104,12 +104,9 @@ public:
 protected:
     void resizeEvent(QResizeEvent *);
 
-private slots:
-    void activateSubWidget();
+private:
     void splitSubWidget(int factoryIndex);
     void closeSubWidget();
-
-private:
     void updateToggleText();
     Internal::NavigationSubWidget *insertSubItem(int position, int index);
     int factoryIndex(Id id);