[collection_frame.jsonld](https://github.com/w3c/web-annotation/blob/gh-pages/jsonld/collection_frame.jsonld) contains ``` "type": "Collection", ``` but this type is not defined in [anno.json](https://github.com/w3c/web-annotation/blob/gh-pages/jsonld/anno.jsonld), shoudn't it be `AnnotationCollection` instead... or am I missing something?