Fix notebook rendering

Author: 8bitmp3

site/en/tutorials/reinforcement_learning/actor_critic.ipynb

@@ -211,7 +211,7 @@
         "\n",
         "For `CartPole-v0`, there are four values representing the state: cart position, cart-velocity, pole angle and pole velocity respectively. The agent can take two actions to push the cart left (`0`) and right (`1`), respectively.\n",
         "\n",
-        "Refer to [Gym's Cart Pole documentation page](https://www.gymlibrary.dev/environments/classic_control/cart_pole/) and ["Neuronlike adaptive elements that can solve difficult learning control problems"](http://www.derongliu.org/adp/adp-cdrom/Barto1983.pdf) by Barto, Sutton and Anderson (1983) for more information.\n"
+        "Refer to [Gym's Cart Pole documentation page](https://www.gymlibrary.dev/environments/classic_control/cart_pole/) and [_Neuronlike adaptive elements that can solve difficult learning control problems_](http://www.derongliu.org/adp/adp-cdrom/Barto1983.pdf) by Barto, Sutton and Anderson (1983) for more information.\n"
       ]
     },
     {