Title of document is misleading

[msporny]

From w3c/transitions#348 (comment) ...

@tidoust wrote: I note that the title of the spec is a bit misleading without context. I initially thought that this was about CBOR itself, which surprised me, not about CBOR usage for DID documents. May I suggest to consider renaming the spec slightly e.g. to include "for DID documents" in the title? I do realize it appears in the subtitle, but subtitles are rarely included.

Change the title of the specification to address @tidoust's concern.