Fix sidepanel link

[janfaracik]

Spotted when fixing JUnit's side panel link (jenkinsci/junit-plugin#755) - this plugin also behaves the same way! Just not as noticeable as we hide our side panel.

Also, shout out to the folks at GitHub for this amazing feature:

Saving dumb folks like me that commit to the wrong branch.

Testing done

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests that demonstrate the feature works or the issue is fixed