content: link search results to overview tab from template
content: link search results to overview tab from template

Updates b/143953613

Change-Id: I70a9701d09773c31f4fc4d3ceb2e913dc0759155
Reviewed-on: https://team-review.git.corp.google.com/c/golang/discovery/+/596642
Reviewed-by: Andrew Bonventre <682ad9f487f614f19e8b7cc5d340bdc8e1c1b128@google.com>

golang/pkgsite,golang/pkgsite,golang/pkgsite,golang/pkgsite