Issue 3208 - Improve JSDoc comments

lib/contentPolicy.js

Index: lib/contentPolicy.js
===================================================================
--- a/lib/contentPolicy.js
+++ b/lib/contentPolicy.js
@@ -29,47 +29,48 @@ let {Prefs} = require("prefs");
 let {FilterStorage} = require("filterStorage");
 let {BlockingFilter, WhitelistFilter, RegExpFilter} = require("filterClasses");
 let {defaultMatcher} = require("matcher");
 let {objectMouseEventHander} = require("objectTabs");
 let {ElemHide} = require("elemHide");
 
 /**
  * Randomly generated class name, to be applied to collapsed nodes.
+ * @type string
  */
 let collapsedClass = "";
 
 /**
  * Public policy checking functions and auxiliary objects
  * @class
  */
 var Policy = exports.Policy =
 {
   /**
    * Set of explicitly supported content types
-   * @type Set
+   * @type Set.<string>
    */
   contentTypes: new Set([
     "OTHER", "SCRIPT", "IMAGE", "STYLESHEET", "OBJECT", "SUBDOCUMENT", "DOCUMENT",
     "XMLHTTPREQUEST", "OBJECT_SUBREQUEST", "FONT", "MEDIA", "ELEMHIDE", "POPUP",
     "GENERICHIDE", "GENERICBLOCK"
   ]),
 
   /**
    * Set of content types that aren't associated with a visual document area
-   * @type Set
+   * @type Set.<string>
    */
   nonVisualTypes: new Set([
     "SCRIPT", "STYLESHEET", "XMLHTTPREQUEST", "OBJECT_SUBREQUEST", "FONT",
     "ELEMHIDE", "POPUP", "GENERICHIDE", "GENERICBLOCK"
   ]),
 
   /**
    * Map containing all schemes that should be ignored by content policy.
-   * @type Set
+   * @type Set.<string>
    */
   whitelistSchemes: new Set(),
 
   /**
    * Called on module startup, initializes various exported properties.
    */
   init: function()
   {