Help Window: Add Bookmarks view

Change-Id: I8b4db5b3208c4133466fe4e61f1dd1f18b432fea
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/help/helpwidget.h

@@ -141,6 +141,7 @@ private:
     Core::MiniSplitter *m_sideBarSplitter;
     Core::SideBar *m_sideBar;
     QAction *m_indexAction;
+    QAction *m_bookmarkAction;
 };
 
 } // Internal