Update _toc.yml

Author: ebatty

_toc.yml

@@ -70,13 +70,13 @@ parts:
       - file: Week8/Video82.ipynb
       - file: Week8/Week8Tutorial1.ipynb 
       - file: Week8/Week8Tutorial2.ipynb 
-  # - caption: Machine Learning
-  #   chapters:
-  #   - file: Week9/Overview.md
-  #     sections:
-  #     - file: Week9/Video91.ipynb
-  #     - file: Week9/Video92.ipynb
-  #     - file: Week9/Video93.ipynb 
+  - caption: Machine Learning
+    chapters:
+    - file: Week9/Overview.md
+      sections:
+      - file: Week9/Video91.ipynb
+      - file: Week9/Video92.ipynb
+      - file: Week9/Video93.ipynb 
   #     - file: Week9/Week9Tutorial1.ipynb 
   #   - file: Week10/Overview.md
   #     sections: