fix: convert raw command in manual to text

src/beamerthememoloch.dtx

@@ -56,7 +56,7 @@
 % them with ``tikzexternalenable'' and ``tikzexternaldisable''. However, if the
 % ``external'' libray is not loaded we would get undefined control sequence
 % problems, hence we define them as no-ops if they are not defined yet.
-% We do the same for the \mmzUnmemoizable command from the memoize package, in
+% We do the same for the ``mmzUnmemoizable'' command from the memoize package, in
 % order to avoid memoization of the progress bars.
 %
 %    \begin{macrocode}