Unable to use highlightjs-glimmer

This is directly related to: https://github.com/josemarluedke/docfy/issues/93 

But, I wanted to open a separate issue for it, because [highlightjs-glimmer](https://hljs-glimmer.nullvoxpopuli.com/) is the only way we get proper highlighting (handlebars highlighting is trash, because we don't use handlebars)