Update draft-ietf-scitt-architecture.md

draft-ietf-scitt-architecture.md

@@ -328,7 +328,7 @@ Most of the details of the Receipt's contents are specified in the COSE Signed M
 
 {{fig-concept-relationship}} illustrates entities and processes that comprise a Transparency Service independent of any one use case.
 
-There are three main entities and their associated processes in SCITT:
+This section describes the three main roles and associated processes in SCITT:
 
 * Issuers that use Statements about Artifacts and their credentials to create Signed Statements
 * Transparency Services that register Signed Statements and Transparent Statements and in doing produce Receipts