“light” is undocumented

[jingsam]

[1ec5]

This root property was added in #495. Indeed, it’s missing a doc property in the JSON schema. Until #495, each root property in the schema had specific properties defined, like type, doc, and sdk-support. light instead has properties that correspond to properties in the resulting JSON stylesheet. It should follow the model of transition: $root.light.type should be set to light, then light should be a property at the top level, set to the object that $root.light is currently set to.

/cc @lbud

[1ec5]

A fix is ready in #542.