Upstream type-scoped context impact

[azaroth42]

This issue w3c/json-ld-syntax#174 for JSON-LD 1.1 doesn't directly affect /our/ context, but we should set it up such that others aren't affected by it when importing linked art into their own contexts.

The issue can be deferred as it doesn't directly affect the model or representation, but needs to be taken into account once JSON-LD 1.1 lands.

[azaroth42]

Closing, as the upstream issue is resolved.