Fix error in commented out code, fixes ageron#89

Author: ageron

18_reinforcement_learning.ipynb

@@ -1934,7 +1934,7 @@
     "        #target_weights = target.get_weights()\n",
     "        #online_weights = model.get_weights()\n",
     "        #for index in range(len(target_weights)):\n",
-    "        #    target_weights[index] = 0.99 * target_weights[index] + 0.01 * target_weights[index]\n",
+    "        #    target_weights[index] = 0.99 * target_weights[index] + 0.01 * online_weights[index]\n",
     "        #target.set_weights(target_weights)\n",
     "\n",
     "model.set_weights(best_weights)"