Correct asset paths

[jonathonherbert]

What does this change?

445 introduced a routing change that broke the site assets. This PR fixes.

How to test

Run locally, and in CODE. You should see:

• [x] the site content load as normal (JS, CSS and asset files like fonts are correct)
• [ ] the favicon appear as normal

Tested:

• [x] locally
• [x] on CODE

NB: I had to check in Firefox for the favicon to appear correctly – there appears to be some weird favicon caching in Chrome! Checking the path in the markup manually should verify if it's not appearing straight away in Chrome and you're unsure.

[samanthagottlieb]

The favicon is appearing like this for me locally:

However it looks fine on CODE.