Update release notes

Author: legrego

docs/changelog/132766.yaml

@@ -4,8 +4,7 @@ area: Authorization
 type: deprecation
 issues: []
 deprecation:
-  title: Change `reporting_user` role to leverage reserved kibana privileges
+  title: Deprecate the built-in `reporting_user` role.
   area: Authorization
-  details: Please describe the details of this change for the release notes. You can
-    use asciidoc.
-  impact: Please describe the impact of this change to users
+  details: The `reporting_user` role is deprecated. Administrators should manage access to Kibana's reporting features via custom roles which grant the necessary privileges.
+  impact: This role will be removed in a future version. Administrators should migrate to custom roles to avoid interruption.