Created by: bardiharborow
Fixes #21265 (closed) by adding a redirect. Fixes #21252 (closed) by refactoring the sidebar active link logic to use strict matching of slugs rather than contains.
Note that the {% if slug == "examples" %} part has been removed as don't / no longer (?) have examples in the sidebar and we now have correct handling of single page groups (e.g. Migration).