Drop `printJSON`
Drop `printJSON`

This function is unused, except by its own recursion. Plus, we should
prefer to use `JSON.stringify` for this, instead of writing our own JSON
printer.

Ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

iFixit/node-markup,iFixit/node-markup,iFixit/node-markup