Per Google's SEO best practices each page with the same content in different languages should have an HREFlang tag (https://support.google.com/webmasters/answer/189077).
VERIFY that all prefixed pages have an HREFlang tag to both itself and the other prefixed versions of that page
Should be feature flagged ()
# There is a module for HREFlang, but we probably cannot use it because of our /en/ special case. We should check.
Might be able to modify for our use case.