Internal doc links don't work

[viridia]

On the npmjs.com page (https://www.npmjs.com/package/astronomy-engine) there are a lot of links which have UR: fragment identifiers:

https://www.npmjs.com/package/astronomy-engine#HelioVector

However, clicking on these links does nothing - it looks like whatever markdown-to-HTML converter is being used doesn't include the anchor elements which would cause the page to scroll down to the linked topic.