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

guacamole-ext/src/main/java/org/apache/guacamole/form/TimeZoneField.java

@@ -20,8 +20,9 @@
 package org.apache.guacamole.form;
 
 /**
- * Represents a time zone field. The field may contain only valid time zone IDs,
- * as dictated by TimeZone.getAvailableIDs().
+ * Represents a time zone field. The field may contain only valid time zone
+ * identifiers, as defined by the IANA time zone database. Such identifiers are
+ * also valid Java time zone IDs as dictated by TimeZone.getAvailableIDs().
  */
 public class TimeZoneField extends Field {
 

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) {