Parse YAML workaround. See #875.

[ioggstream]

This PR

• modify the parser to accept YAML instead of JSON

Notes

I tried to bundle the editor with npm run build:editor, but it does not seem to work on my PC, while just modifying the .js works.

[davidlehn]

• Certainly need to update the source for any such change. The generated code will be overwritten.
• This is probably a more involved discussion. The playground code doesn't yet handle the YAML-LD spec. I'm guessing you at least want the minimal feature of parsing JSON-LD that was serialized as YAML. That's fine, but I think the playground should also be able to have a mode that only accepts valid JSON. Which probably means the parsing type needs to be a choice. I'm not sure how that should all work.