Update app.py

app.py

@@ -845,7 +845,7 @@ class Visualization:
             "This demo can be a little slow, and only allows you to process up to 5000 documents "
             "for a decent speed. If you want to display up to three times more documents and have "
             "a faster visualization, we invite you to run this "
-            "[code](https://github.com/bigscience-workshop/data_tooling/tree/master/ac_dc/visualization) "
+            "[code](https://github.com/bigscience-workshop/data-preparation/tree/main/preprocessing/filtering/visualization) "
             "on your computer."
         )