remove unneeded traitlets imports and document that the link and dlin…

…k are re-exported by ipywidgets

docs/source/examples/Widget Events.ipynb

@@ -250,18 +250,7 @@
    "source": [
     "### Linking traitlets attributes in the kernel\n",
     "\n",
-    "The first method is to use the `link` and `dlink` functions from the `traitlets` module. This only works if we are interacting with a live kernel."
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 6,
-   "metadata": {
-    "collapsed": true
-   },
-   "outputs": [],
-   "source": [
-    "import traitlets"
+    "The first method is to use the `link` and `dlink` functions from the `traitlets` module (these two functions are re-exported by the `ipywidgets` module for convenience). This only works if we are interacting with a live kernel."
    ]
   },
   {
@@ -651,7 +640,6 @@
     }
    ],
    "source": [
-    "import traitlets\n",
     "a = widgets.IntSlider(description=\"Delayed\", continuous_update=False)\n",
     "b = widgets.IntText(description=\"Delayed\", continuous_update=False)\n",
     "c = widgets.IntSlider(description=\"Continuous\", continuous_update=True)\n",