Add links behind nav entries "Namespaces" and "Files" (matching "Clas…

…ses")

When layout file has "namespacelist" resp. "filelist" set to visible=no,
the files "namespaces.html" resp. "files.html" are still generated,
but not reachable. So same fix as done for "classlist" should be used,
cmp. 700a9ac

Also gives consistent result & at least in QCH files fix the error
message shown when clicking on "Namespaces" or "Files" section titles.

src/index.cpp

@@ -4122,7 +4122,7 @@ static void writeIndexHierarchyEntries(OutputList &ol,const QList<LayoutNavEntry
             {
               if (documentedNamespaces>0 && addToIndex)
               {
-                Doxygen::indexList->addContentsItem(TRUE,lne->title(),0,0,0); 
+                Doxygen::indexList->addContentsItem(TRUE,lne->title(),0,lne->baseFile(),0);
                 Doxygen::indexList->incContentsDepth();
                 needsClosing=TRUE;
               }
@@ -4189,7 +4189,7 @@ static void writeIndexHierarchyEntries(OutputList &ol,const QList<LayoutNavEntry
             {
               if (documentedHtmlFiles>0 && addToIndex)
               {
-                Doxygen::indexList->addContentsItem(TRUE,lne->title(),0,0,0); 
+                Doxygen::indexList->addContentsItem(TRUE,lne->title(),0,lne->baseFile(),0);
                 Doxygen::indexList->incContentsDepth();
                 needsClosing=TRUE;
               }