Remove all uses of \sectcode; we can now use logical markup everywhere.
diff --git a/Doc/lib/libmarshal.tex b/Doc/lib/libmarshal.tex
index a2a8084..5878cfa 100644
--- a/Doc/lib/libmarshal.tex
+++ b/Doc/lib/libmarshal.tex
@@ -1,4 +1,4 @@
-\section{Built-in Module \sectcode{marshal}}
+\section{Built-in Module \module{marshal}}
 \label{module-marshal}
 \bimodindex{marshal}