Remove all uses of \sectcode; we can now use logical markup everywhere.
diff --git a/Doc/lib/libthread.tex b/Doc/lib/libthread.tex
index 1307619..9e9d8ba 100644
--- a/Doc/lib/libthread.tex
+++ b/Doc/lib/libthread.tex
@@ -1,4 +1,4 @@
-\section{Built-in Module \sectcode{thread}}
+\section{Built-in Module \module{thread}}
 \label{module-thread}
 \bimodindex{thread}