Update Cross-Domain Overview

[bradleycamacho]

Description

https://docs.optimism.io/stack/transactions/cross-domain

Update the diagrams (if needed) and content with Fault Proof info

Action items

1. Do research on topic and raise any questions with the docs team
2. Write a first draft. It doesn't have to be worded perfectly as the docs team will review
3. Ping @bradleycamacho or @krofax on discord and request review
4. Implement feedbacks from @bradleycamacho and @krofax
5. Publish