Add header block on C API notebook

docs/source/examples/index.rst

@@ -19,7 +19,7 @@ General Usage
     post-processing
     pandas-dataframes
     tally-arithmetic
-    CAPI
+    capi
     expansion-filters
     search
     nuclear-data

examples/jupyter/capi.ipynb

@@ -4,6 +4,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
+    "# Using the C/C++ API\n",
     "This notebook shows how to use the OpenMC C/C++ API through the openmc.lib module. This module is particularly useful for multiphysics coupling because it allows you to update the density of materials and the temperatures of cells in memory, without stopping the simulation.\n",
     "\n",
     "Warning: these bindings are still somewhat experimental and may be subject to change in future versions of OpenMC."
@@ -466,7 +467,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.0"
+   "version": "3.8.3"
   }
  },
  "nbformat": 4,