add embedded shell to ToC

Author: jeff-allen-mongo

source/index.txt

@@ -168,9 +168,9 @@ suit your needs.
       /connect
       /instance
       /manage-data
-      /aggregation-pipeline-builder
       /import-export
       /embedded-shell
+      /aggregation-pipeline-builder
       /troubleshooting
       /faq
       /learn-more