amp.dev should link to this repo

## Feature Request

# Is your feature request related to a problem? Please describe.

1. Go to https://amp.dev/about/use-cases/
1. I was expecting it to have a list of AMP use cases, and it didn't, so I wanted to send feedback
1. Look for a link to https://github.com/ampproject/amp.dev from amp.dev
1. When you click the GitHub icon, it takes you to the AMP organization page... you have to search for the amp.dev repo

# Describe the solution you'd like

Add an "improve this article" or "send feedback on this doc" link or something that takes you to the amp.dev repo

# Describe alternatives you've considered

I donno

# Optional: Teachability, Documentation, Adoption, Migration Strategy

> If you can... possibly write out a version the docs.

Good try! :D