No example for collectionGroup for Firestore V9 (modular) in the documentation

I'm upgrading a Firebase app to version 9, and I can't find in the documentation how `collectionGroup` is used.

This is an example from the current documentation

And here is the corresponding code snippet:
https://github.com/firebase/snippets-web/blob/1e8f41c904d557f486cdab2a1401ec5f6033dc39/firestore/test.firestore.js#L1089-L1094

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From the code snippets [here](https://github.com/firebase/snippets-web/blob/1e8f41c904d557f486cdab2a1401ec5f6033dc39/snippets/firestore-next/test-firestore/fs_collection_group_query.js) on GitHub it seems like it has been already implemented, yet it doesn't appear in the documentation.
https://github.com/firebase/snippets-web/blob/1e8f41c904d557f486cdab2a1401ec5f6033dc39/snippets/firestore-next/test-firestore/fs_collection_group_query.js#L8-L14