Add _.cloneDeep doc note to _.clone too. [ci skip]

lodash.js

@@ -5212,6 +5212,12 @@
      * callback returns `undefined` cloning will be handled by the method instead.
      * The callback is bound to `thisArg` and invoked with one argument; (value).
      *
+     * Note: This method is loosely based on the structured clone algorithm. Functions
+     * and DOM nodes are **not** cloned. The enumerable properties of `arguments` objects and
+     * objects created by constructors other than `Object` are cloned to plain `Object` objects.
+     * See the [HTML5 specification](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm)
+     * for more details.
+     *
      * @static
      * @memberOf _
      * @category Objects