Used more pythonic commands in plotter module and commented the block which obtains MGXS data for plotting

docs/source/pythonapi/examples/mgxs-part-ii.ipynb

@@ -1975,7 +1975,7 @@
     "\n",
     "One particularly useful visualization is a comparison of the continuous-energy and multi-group cross sections for a particular nuclide and reaction type. We illustrate one option for generating such plots with the use of the `openmc.plotter` module to plot continuous-energy cross sections from the openly available cross section library distributed by NNDC.\n",
     "\n",
-    "There is a simpler way to plot the MGXS data (using the same interface as is used for the continuous-energy data), however this example series has not yet introduced the pre-requisite information and so we will do this manually here."
+    "The MGXS data can also be plotted using the openmc.plot_xs command, however we will do this manually here to show how the openmc.Mgxs.get_xs method can be used to obtain data."
    ]
   },
   {