Fix incorrect statement in securing expectations.

Co-authored-by: Brent Zundel <[email protected]>

index.html

@@ -3011,7 +3011,7 @@ <h3>Trust Model</h3>
 either of the following:
             <ul>
               <li>
-A [=verifier=] is expected to secure a [=credential=] with a 
+An [=issuer=] is expected to secure a [=credential=] with a 
 <a href="#securing-mechanisms">securing mechanism</a> which establishes
 that the [=issuer=] generated the [=credential=]. (In other words, an
 [=issuer=] is expected to [=issue=] a [=verifiable credential=].)