remove wald_friedman and open an issue re: jupytext

Author: mmcky

lectures/_toc.yml

@@ -52,7 +52,7 @@
   chapters:
     - file: odu
     - file: likelihood_ratio_process
-    - file: wald_friedman
+    # - file: wald_friedman
     - file: exchangeable
     - file: likelihood_bayes
     - file: navy_captain