Show panel (with references/etc.) UI in code host integrations

[sqs]

This is about the browser extension showing the find-references/etc. panel on code hosts instead of making the "Find references" action take you away from your code host to Sourcegraph.

TODO add more details, user stories, etc.

[sqs]

Relevant feedback from a friend who is a PM/analyst at Google:

"It wasn't clear that go-to-definition would keep me on GitHub but find-references would take me off-site. I actually liked the code browser on Sourcegraph.com a lot (it is good like our internal Google code search), and I started using it more, but it is still weird to jump me between sites."

[uwedeportivo]

Dear all,

This is your release captain speaking. 🚂🚂🚂

Branch cut for the 3.17 release is scheduled for tomorrow.

Is this issue / PR going to make it in time? Please change the milestone accordingly.
When in doubt, reach out!

Thank you

[macraig]

Closing due to inactivity.