be more explicit that VC examples do not define anything

[bc-pi]

be more explicit that the VCDM and SD-JWT VC examples are only illustrative and do not define anything (for #341)

preview links to the two relevant appendix parts: https://drafts.oauth.net/oauth-selective-disclosure-jwt/examples-are-only-examples/draft-ietf-oauth-selective-disclosure-jwt.html#appendix-A

https://drafts.oauth.net/oauth-selective-disclosure-jwt/examples-are-only-examples/draft-ietf-oauth-selective-disclosure-jwt.html#appendix-A.4

[Sakurann]

discussed to add a sentence at line 1513 that data structure and claim names are hypothetical. @sakurann to do

[bc-pi]

discussed to add a sentence at line 1513 that data structure and claim names are hypothetical. @Sakurann to do

Perspective text from SD-JWT VC that tries to say similar things:

Important: The following examples are not normative and provided for illustration illustrative purposes only. In particular, neither the structure of the claims nor the selection of selectively disclosable claims are normative.

[bc-pi]

discussed to add a sentence at line 1513 that data structure and claim names are hypothetical. @Sakurann to do

Perspective text from SD-JWT VC that tries to say similar things:

Important: The following examples are not normative and provided for ~illustration~ illustrative purposes only. In particular, neither the structure of the claims nor the selection of selectively disclosable claims are normative.

I added that text at start of the whole examples appendix 0bd026ba5f802a79c790822f875ea348647fb11c

And updated the text at the start of the VCDM example along the lines of @Sakurann's suggestion 30c847c605fd06064ade786ff9c3f134b9ff32af

I think this one is ready for review again.

[bc-pi]

The only changes Dr. @danielfett hasn't seen since he approved are text he wrote/suggested borrowed from SD-JWT VC so I think it's ok to go ahead and merge.