feat: modify bullet symbols for itemize lists

src/beamerinnerthememoloch.dtx

@@ -479,7 +479,9 @@
 % \subsubsection{Lists and floats}
 %
 %    \begin{macrocode}
-\setbeamertemplate{itemize items}{\textbullet}
+\setbeamertemplate{itemize item}{\(\bullet\)}
+\setbeamertemplate{itemize subitem}{\(\circ\)}
+\setbeamertemplate{itemize subsubitem}{\textbullet}
 \setbeamertemplate{caption label separator}{: }
 \setbeamertemplate{caption}[numbered]
 %    \end{macrocode}