Right side ToC doesn't update when scrolling the page

[dlespiau]

At the moment, we use the mode of the vue router when the route of the document is encoded as the URL hash. This is done to now have to reload the whole page every time we change page.

The issue is with scrollspy-nav. It needs the id of the element to equal the content of href. As soon as we put a / in href and ids, scrollspy-nav stops working. Would need to find out why.