Code fence doesn't pass through info string about markdoc HOT 2 CLOSED

Markdoc automatically parses annotations that are passed into the fence info line, so you can do:

```js {% test=true %}
...
```

And the fence AST node will have a test attribute with the boolean value true. Does that feature satisfy your use case or do you still want to get the raw info line?

It looks like we've had some previous requests for this, so I'm open to adding it if it's genuinely useful, but would ideally like to encourage use of the annotations over custom handling of the raw info line.

from markdoc.

Amazing @rpaul-stripe - that is exactly what I need. Thanks a bunch! 🎉

from markdoc.