docs: apply changes mentioned in discussion

src/things/message.ts

@@ -30,12 +30,12 @@ import {SCOrganizationWithoutReferences} from './organization';
 export interface SCMessageWithoutReferences
   extends SCCreativeWorkWithoutReferences {
   /**
-   * Recipients of the message
+   * Organizational unit for which the message is intended
    */
   audienceOrganizations?: SCOrganizationWithoutReferences[];
 
   /**
-   * Audience of the message
+   * Roles for which the message is intended
    */
   audiences: SCMessageAudience[];