improve tutorial_05 docstring

Author: bobmyhill

tutorial/tutorial_05_equilibrium.ipynb

@@ -112,7 +112,8 @@
         "print(sol.assemblage)\n",
         "\n",
         "# The total entropy of the assemblage is the molar entropy\n",
-        "# multiplied by the number of moles in the assemblage.\n",
+        "# multiplied by the number of moles in the assemblage. This can be\n",
+        "# accessed either by sol.assemblage.entropy, or by the shorter alias:\n",
         "entropy = sol.assemblage.S"
       ]
     },