Fix: do not add an existing version in the index

updateIndex.py

@@ -35,7 +35,8 @@ def updateIndex(args:argparse.Namespace) -> None:
                 element_to_delete.decompose()
             else:
                 print("Element not found.")
-
+    elif soup.find('li', text=args.documentName):
+        print("'index.html' does already contain the entry")
     else:
         # Find document list
         # Assume there's a list (<ul>) with id "document-list"