The Danish translation is not yet linked in the language selector
since it is very incomplete. This means that `selectedLang` is `null`
in this case and thus we should not call any methods on it.
The picker is a drop-down menu using the same design as the theme
picker in the top-left.
There doesn’t seem to be an easy way to pass in a list of languages
and descriptions, so for now we’ll have to expand the menu by hand as
we add new languages. A comment has been added to `publish.yml` to
remind us of this.
This replaces a bit of code with the equivalent HTML code.
We also load the script async, which means that the browser won’t
block rendering while waiting for the scripts.
This will allow us to customize the appearance more easily: we can
move the GA logic into the theme (to reduce load times and to simplify
the JS injection logic). We can also add new elements, which is what I
will do next.
The mdbook theme can be added incrementally: if we don’t add a file to
our theme folder, we will get the corresponding file from mdbook.
