docs: Fetch like Filters

[MentalGear]

It'd be great if Fetch would have it's nav just like 'Filters' subsection. I search the docs for a while before I noticed that there are tiny toggles on the right to show how to query for foreign fields in a select, and I think many people overlook this as well. Searching for it in the docs yields no real results, and also google has no good index entry point if you hide this most crucial feature behind a tiny side toggle.
https://supabase.com/docs/reference/javascript/select