Fix formatting of update message in xkcd1313 notebook

ipynb/xkcd1313.ipynb

@@ -904,7 +904,7 @@
     }
    },
    "source": [
-    "**Update (Nov 2015): There are two new movies in the works! **\n",
+    "**Update (Nov 2015): There are two new movies in the works!**\n",
     "\n",
     "<table><tr><td>\n",
     "<img src=\"https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTmuo_ARTOtkU5vzJ50jVUmmwpboU8KaNy6wjmxDPcUtPzaUmXyBg\" width=300>\n",