doc(mf6io): fix PRT MIP section in IO guide (#1931)

MIP options block was omitted from structure of blocks section. Closes #1929.

Author: wpbonelli

doc/mf6io/prt/mip.tex

@@ -2,7 +2,7 @@
 
 \vspace{5mm}
 \subsubsection{Structure of Blocks}
-%%\lstinputlisting[style=blockdefinition]{./mf6ivar/tex/prt-mip-options.dat}
+\lstinputlisting[style=blockdefinition]{./mf6ivar/tex/prt-mip-options.dat}
 \lstinputlisting[style=blockdefinition]{./mf6ivar/tex/prt-mip-griddata.dat}
 
 \vspace{5mm}