PR page changed, browser ext not working

Created by: sqs

https://github.com/sourcegraph/go-diff/pull/31/files#diff-334200dfc76f817e050f8dc5d9745843R19

No Sourcegraph buttons show up.

I thought (originally) that hovers were also not showing up, but they actually are working fine. So the problem is just that no Sourcegraph contributed actions or buttons show up.