Add .js to include lang mapping
Add .js to include lang mapping

Prism does recognize 'js' as a valid language, but only if
prism-javascript.min.js is loaded first. If there are no code blocks
with `class="language-javascript"`, then an included .js file won't
get highlighted. This should fix that.
hotdoc/hotdoc,thiblahute/hotdoc,thiblahute/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc