Export definitions for reSpec

[evanp]

The definitions used in the Activity Streams 2.0 Core and Vocabulary documents should be available to other reSpec documents.

https://respec.org/docs/#data-export

[evanp]

I think this is a markup issue, so could be updated without a version change for the spec. I can check with @plehegar about if that's possible.

[plehegar]

I think this is a markup issue, so could be updated without a version change for the spec. I can check with @plehegar about if that's possible.

indeed. those would be editorial changes so easy to make.