GUACAMOLE-422: Update TIMEZONE field documentation to reference IANA time zone database.

guacamole/src/main/webapp/app/form/controllers/timeZoneFieldController.js

@@ -19,8 +19,9 @@
 
 
 /**
- * Controller for time zone fields. Time zone fields use Java IDs as the
- * standard representation for each supported time zone.
+ * Controller for time zone fields. Time zone fields use IANA time zone
+ * database identifiers as the standard representation for each supported time
+ * zone. These identifiers are also legal Java time zone IDs.
  */
 angular.module('form').controller('timeZoneFieldController', ['$scope', '$injector',
     function timeZoneFieldController($scope, $injector) {