Watchers, tips for beginners: Mention options `immediate` and `deep`

[michapietsch]

Hey,

I'd like to offer to prepare a PR with a few lines to the guide to address beginners questions regarding watchers.

When I started, sometimes I wondered: "Why doesn't my watcher seem to run?"

In addition to the API docs, my understanding is that the guide provides a different angle/approach, especially for beginners, although I also go to the API docs to learn more.

I'd ask for quick feedback if you'd like the guide to expand that far, or maybe it has intentionally been left out.

[bencodezen]

Hi @michapietsch! Thanks for your offer to update the watcher section. At this time, we're currently focused on efforts for the v3 docs. As a result, happy to mark this as post-3.0 for us to discuss once the team has more bandwidth to update the v2 docs.

If you have any other questions, please let me know!