Fix link to stack.

samples/core/get_started/eager.ipynb

@@ -399,7 +399,7 @@
       "source": [
         "To simplify the model building, let's repackage the features dictionary into an array with shape ``(batch_size,num_features)`.\n",
         "\n",
-        "To do this we'll write a simple function using the [tf.stack](https://www.tensorflow.org/api_docs/python/tf/data/dataset/map) method to pack the features into a single array. Then we'll use the [tf.data.Dataset.map](https://www.tensorflow.org/api_docs/python/tf/data/dataset/map) method to apply this function to each `(features,label)` pair in the dataset. :\n"
+        "To do this we'll write a simple function using the [tf.stack](https://www.tensorflow.org/api_docs/python/tf/stack) method to pack the features into a single array. Then we'll use the [tf.data.Dataset.map](https://www.tensorflow.org/api_docs/python/tf/data/dataset/map) method to apply this function to each `(features,label)` pair in the dataset. :\n"
       ]
     },
     {