Minor notebook cleanup

Author: kavanase

examples/tlc.ipynb

@@ -190,8 +190,6 @@
     "\n",
     "An easy way to check this is to print `tlc.scfermi.fermi_level` after running the TLC calculation below (to check it matches your expected Fermi level position), and to print the calculated defect concentrations with:\n",
     "\n",
-    ".. code-block:: python\n",
-    "\n",
     "    for defect in tlc.scfermi.defects:\n",
     "        print(defect.name, f\"{defect.concnt:.2e}\")\n",
     "```"