Update rbac.md

Documentation for kubernetes/enhancements#789

content/en/docs/reference/access-authn-authz/rbac.md

@@ -489,14 +489,19 @@ NOTE: editing the role is not recommended as changes will be overwritten on API
 </tr>
 <tr>
 <td><b>system:basic-user</b></td>
-<td><b>system:authenticated</b> and <b>system:unauthenticated</b> groups</td>
+<td><b>system:authenticated</b> group</td>
 <td>Allows a user read-only access to basic information about themselves.</td>
 </tr>
 <tr>
 <td><b>system:discovery</b></td>
-<td><b>system:authenticated</b> and <b>system:unauthenticated</b> groups</td>
+<td><b>system:authenticated</b> group</td>
 <td>Allows read-only access to API discovery endpoints needed to discover and negotiate an API level.</td>
 </tr>
+<tr>
+<td><b>system:public-info-viewer</b></td>
+<td><b>system:authenticated</b> and <b>system:unauthenticated</b> groups</td>
+<td>Allows read-only access to non-sensitive cluster information.</td>
+</tr>
 </table>
 
 ### User-facing Roles