Clarify what happens when an interceptor doesn't have any @AroundInvoke or lifecycle annotation

At the moment, if you enable an interceptor in beans.xml and the class is not annotated with @Inteceptor, WELD throws an exception. But if the interceptor has no @AroundInvoke, @AroundConstrcut, @PostConstruct or @PreDestroy, then WELD stays silent and the interceptor doesn't work.

The spec should clarify that, at least, one of these four annotation has to be used otherwise it's not considered a valid interceptor.