Add warning to shutdown() javadoc method of CouchbaseEnvironment

Currently in our docs for using CouchbaseEnvironment between multiple buckets we explicitly state that you should close all connected buckets + clusters before shutting down the environment:
https://developer.couchbase.com/documentation/server/4.6/sdk/java/managing-connections.html#concept2677__concurrency

Would it also be possible to get this warning added to appropriate places in the java doc too, since developers may not read the main docs page?

For example http://docs.couchbase.com/sdk-api/couchbase-core-io-1.5.3/com/couchbase/client/core/env/CoreEnvironment.html#shutdown--