Make clear that digital sig section applies to jwt proof type too

Already nominally the case given it's specified for the key binding
jwt, but this makes it much clearer.

closes #342

Author: jogu

openid4vc-high-assurance-interoperability-profile-1_0.md

@@ -352,6 +352,7 @@ Issuers, Verifiers, and Wallets MUST, at a minimum, support ECDSA with P-256 and
 - Issuers
   - Wallet Attestations (including PoP) when Annex E of [@!OIDF.OID4VCI] is used;
   - Key Attestations when Annex D of [@!OIDF.OID4VCI] is used.
+  - `jwt` proof type as specified in Annex E of [@!OIDF.OID4VCI]
 - Verifiers
   - the signature of the Verifiable Presentation, e.g., KB-JWT of an SD-JWT VC, or `deviceSignature` CBOR structure in case of ISO mdocs. Verifiers are assumed to determine in advance the cryptographic suites supported by the ecosystem, e.g. mDL Issuers/Verifiers implementing ISO mdocs.
   - the status information of the Verifiable Credential or Wallet Attestation.