Code blocks without a language lose line breaks

See, e.g. pseudocode blocks at http://scijs.net/packages/#scijs/ndarray-gram-schmidt-qr-complex

Blocks without a language seem to lose line breaks. `./highlight.js` has:

``` javascript
function highlight (code, lang, done) {
  if (!lang) return done(null, code)
```

So maybe bailing out with a no-op fails to massage the data correctly?
