Remove outdated TODOs.

Author: MarkDaoust

site/en/tutorials/eager/automatic_differentiation.ipynb

@@ -268,10 +268,8 @@
       "source": [
         "x = tf.ones((2, 2))\n",
         "  \n",
-        "# TODO(b/78880779): Remove the 'persistent=True' argument and use\n",
         "# a single t.gradient() call when the bug is resolved.\n",
         "with tf.GradientTape(persistent=True) as t:\n",
-        "  # TODO(ashankar): Explain with \"watch\" argument better?\n",
         "  t.watch(x)\n",
         "  y = tf.reduce_sum(x)\n",
         "  z = tf.multiply(y, y)\n",
@@ -315,8 +313,6 @@
       },
       "outputs": [],
       "source": [
-        "# TODO(ashankar): Should we use the persistent tape here instead? Follow up on Tom and Alex's discussion\n",
-        "\n",
         "x = tf.constant(1.0)  # Convert the Python 1.0 to a Tensor object\n",
         "\n",
         "with tf.GradientTape() as t:\n",