[Openid-specs-ab] Issue #1422: 5. vp_token encoding (openid/connect)

[Nat]

New issue 1422: 5. vp_token encoding
https://bitbucket.org/openid/connect/issues/1422/5-vp_token-encoding

Nat Sakimura:

Section 5 defines vp\_token as a response parameter 

* `vp_token`: a parameter that either directly contains a verifiable presentation or a JSON array with multiple verifiable presentations.

It was not immediately clear how this is encoded. Adding some explanatory text will help readability.