fix for CHM TOC "Classes" entry to point to annotated file

bug: when layout file disables Class List but Classes are still visible
the related TOC entry of Compiled HTML Help file does not link to any
page, so the annotated.html file is not reachable from the TOC tree even
though it still gets generated

src/index.cpp

@@ -4140,7 +4140,7 @@ static void writeIndexHierarchyEntries(OutputList &ol,const QList<LayoutNavEntry
         case LayoutNavEntry::Classes: 
           if (annotatedClasses>0 && addToIndex)
           {
-            Doxygen::indexList->addContentsItem(TRUE,lne->title(),0,0,0); 
+            Doxygen::indexList->addContentsItem(TRUE,lne->title(),0,"annotated",0); 
             Doxygen::indexList->incContentsDepth();
             needsClosing=TRUE;
           }