Table of contents in web version doesn't correctly update URL fragment

[kerrickstaley]

When I visit the URL https://dev.realworldocaml.org/variants.html#polymorphic-variants , it takes me to the "Polymorphic Variants" section of the Variants chapter. This is nice, because this anchor lets you link someone to a specific section.

However, this isn't discoverable, because when I click different headings in the table of contents on that page, it doesn't update the fragment.

It would be great if clicking headings in the table of contents would update the URL fragment.