Regenerate README ToC after adding debugging section

Author: elidlocke

README.md

@@ -82,6 +82,7 @@ informal introduction to the features and their implementation.
         - [Customizing the Sandbox](#customizing-the-sandbox)
           - [Passthrough Modules](#passthrough-modules)
           - [Invalid Module Members](#invalid-module-members)
+        - [Debugging Workflows with `breakpoint()` / `pdb`](#debugging-workflows-with-breakpoint--pdb)
         - [Known Sandbox Issues](#known-sandbox-issues)
           - [Global Import/Builtins](#global-importbuiltins)
           - [Sandbox is not Secure](#sandbox-is-not-secure)