Semantically, I'm unsure if `<aside>` should be the right choice for a notification, as the context changes depending on it's parent element. In this PR, it's placement makes it related to the site as a whole, which works ok i think. It it got moved inside an `<article>` on a given page however, the context would change to be related to the article and not the overall page.

Also, would it be better to have one `<aside>` containing multiple messages, as opposed to more than one `<aside>` at a given time?

But this is all a nit-pick really