Update TnT family docs
Update the track and Trace transaction family docs to correctly
outline the Proposal addressing scheme. This change aligns the docs
with the actual functionality.
@@ -329,8 +329,7 @@ its type:
- The first 36 characters of the hash of the identifier of
its associated Record.
- - The first 22 characters of its ``receiving_agent``.
- - The first 4 characters of the hash of its ``timestamp``.
+ - The first 26 characters of its ``receiving_agent``.
- Record: the first 62 characters of the hash of its identifier.
