getVerificationMethod should be framing the verificationMethod URI

Ed25519Signaute2020#getVerificatoinMethod should frame proof.verificationMethod like the base LinkedDataSignature#getVerificationMethod.

If the framing doesn’t happen within the signature suite the framing/deferencing then it is up to the documentLoader to handle that (which is happening here in the tests). But that puts more requirements on the user to know how to handle framing/deferencing from within their documentLoader (and handling it for all the different sig suites).

[OR13]

To be clear, documentLoaders are “DID Dereferencers”, if they process content type and fragments… thats a step after resolution.

[dlongley]

So I proposed this above:

A possible compromise position would be for the signature suite to first check if the ID of the returned document matches the verification method ID – and, if not, use framing. This would be an automatic process that would avoid framing in cases where the user provided a document loader that fully dereferences DID URLs vs. one that just returns a document in which the referenced entity exists somewhere – leaving the suite to do the rest of the dereferencing via the framing operation.

https://github.com/digitalbazaar/jsonld-signatures/issues/141#issuecomment-834011841

If that were implemented, would it solve everyone’s problems here? Or would something more be required?