Intra-page fragment linking not working with `wouter`

(This can probably be boiled down to `wouter` not reacting to `hashChange` events).

While a link to a page with a fragment/hash now works with `wouter`, fragment linking within a single route/page does not work (nothing happens). Presumably this is because we need to configure `wouter` appropriately.

There's some slightly abstruse documentation about [customizing the location hook in related ways](https://github.com/molefrog/wouter#customizing-the-location-hook) in `wouter`'s README.