doc(eks): stronger wording regarding supported regions, fix table
Created by: bobheadxi
- stronger wording about how EKS is not everywhere yet because if you try to do it in an unsupported region it helpfully complains about permissions instead of telling you EKS is unavailable
- fixes the resources table - funky stuff going on in the docs right now: https://docs.sourcegraph.com/admin/install/kubernetes/eks