This is a funny one, because we were accidentally opening them in the
same window without intending to do so since commit 928312e21, since the
`sanitize` method removes the `target` attribute. So the test we're
adding already passed without these changes.
This way it'll be easier to decide when they should be rendered.
In order to be consistent, we're using the `Layout` module for both
components; previously, the navigation partial was in the `shared`
folder while the footer partial was in the `layout` folder, which IMHO
didn't make much sense.
