Fixing the HTML merge errors

I noticed the [HTML](https://responsiveimagescg.github.io/eq-usecases/) had, what looked like, git merge problems so I re-ran the bikeshed process.

```shell
curl https://api.csswg.org/bikeshed/ -F file=@index.bs -F force=1 > index.html
```

I've never used bikeshed before so I'm not sure if that's exactly right but it looks ok.

Hope that helps - keep up the good work!