GroupsIT: Correct format of Javadoc comment

Directly using @ at the beginning of a comment indicates a tag.

Change-Id: I49f8eb035584b92635e386ac768711d182a9f767
diff --git a/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java b/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
index 852187d..6bc792d 100644
--- a/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
@@ -948,8 +948,8 @@
   }
 
   /**
-   * @Sandboxed is used by this test because it deletes a group reference which introduces an
-   * inconsistency for the group storage. Once group deletion is supported, this test should be
+   * {@code @Sandboxed} is used by this test because it deletes a group reference which introduces
+   * an inconsistency for the group storage. Once group deletion is supported, this test should be
    * updated to use the API instead.
    */
   @Test