fix: fixed title

openid-4-verifiable-presentations-1_0.md

@@ -1544,7 +1544,7 @@ The following is the content of the `presentation_definition` parameter:
 
 <{{examples/response/ac_vp_sd.json}}
 
-## mdoc (ISO/IEC 18013 and ISO/IEC 23220)
+## Mobile Documents or mdocs (ISO/IEC 18013 and ISO/IEC 23220)
 
 ISO/IEC 18013-5:2021 [@ISO.18013-5] defines a mobile driving license (mDL) Credential in the mobile document (mdoc) format. Although ISO/IEC 18013-5:2021 [@ISO.18013-5] is specific to mobile driving licenses (mDLs), the Credential format can be utilized with any type of Credential (or mdoc document types). The ISO/IEC 23220 series has extracted components from ISO/IEC 18013-5:2021 [@ISO.18013-5] and ISO/IEC TS 18013-7 [@ISO.18013-7] that are common across document types to facilitate the profiling of the specification for other document types. The core data structures are shared between ISO/IEC 18013-5:2021 [@ISO.18013-5], ISO/IEC 23220-2 [@ISO.23220-2], ISO/IEC 23220-4 [@ISO.23220-4] which are encoded in CBOR and secured using COSE_Sign1.