Mention the nx graph in the contributing guide (#7001)

* Mention the nx graph in the contributing guide

* add alt

Author: jtpio

CONTRIBUTING.md

@@ -100,6 +100,16 @@ The repository is configured to use the Lerna caching system (via `nx`) for some
 
 This helps speed up rebuilds when running `jlpm run build` multiple times to avoid rebuilding packages that have not changed on disk.
 
+You can generate a graph to have a better idea of the dependencies between all the packages using the following command:
+
+```
+npx nx graph
+```
+
+Running the command will open a browser tab by default with a graph that looks like the following:
+
+![a screenshot showing the nx task graph](https://github.com/jupyter/notebook/assets/591645/34eb46f0-b0e5-44b6-9430-ae5fbd673a4b)
+
 To learn more about Lerna caching:
 
 - https://lerna.js.org/docs/features/cache-tasks