Fix Gerrit revision for open-on-sourcegraph button
Created by: marekweb
In the browser extension, on Gerrit:
When clicking on the "Open on sourcegraph" button in Gerrit, the destination URL was missing the revision.
This fixes the destination URL by making sure that we obtain the current Gerrit revision and provide it in the returned context from codehost.getContext()
, which is used to create the URL.