Documentation suggestions

[leoj3n]

In them main README.md, you might want to change this line from https://github.com/google/code-prettify to https://prismjs.com/.

It also might be nice to add back these lines after updating the text to be correct for Prism so that this page will still exist: https://bit-docs.github.io/bit-docs-website/bit-docs-prettify/prettify.less.html

I think that is a useful page because it demonstrates what the default syntax highlighting looks like.