Update Archetype syntax highlighter to catch both types of comments
Related to https://github.com/completium/archetype-docs/pull/25.
Archetype comments are formatted like c-like languages, so you can have single-line comments that start with // or multi-line comments within /* ... */. The Prism rule in this formatter catches only multiline comments. This PR adds single-line comments. I stole the code from the clike formatter here: https://github.com/PrismJS/prism/blob/master/components/prism-clike.js.