My Wagtail app is configured to managing documents, and I want to include document links via a RichTextField of my page model. The output of the {{ page.body|richtext }} tag is missing a href attribute for document links:

<p data-block-key="c6hgq">
<a id="2" linktype="document">Document title</a>
</p>

I did not configure WAGTAILDOCS_SERVE_METHOD manually in the settings, so the serve_view method should be used according to the docs, but switching to WAGTAILDOCS_SERVE_METHOD = 'direct' does not fix the incomplete link quoted above.

What am I missing here?