Update instructions, for libraries that involve more than just downloading the latest version.
### highlightjs
To update the highlightjs library, first download a plain package (no languages included) [from highlightjs.org](https://highlightjs.org/download/). The `highlight.pack.js` file in the archive should be moved into this `static/js/` directory and renamed to `highlight.min.js`.
Then [download an archive](https://github.com/highlightjs/highlight.js/releases) of the latest version. Extract it to some directory, and replace **~/Downloads/highlight.js** below with the resulting directory.