New section header style.

Fix up a few synopses.
diff --git a/Doc/lib/libmarshal.tex b/Doc/lib/libmarshal.tex
index ab7cd05..a30dd1e 100644
--- a/Doc/lib/libmarshal.tex
+++ b/Doc/lib/libmarshal.tex
@@ -1,8 +1,9 @@
-\section{Built-in Module \module{marshal}}
+\section{\module{marshal} ---
+         Python object serialization (with different constraints).}
 \declaremodule{builtin}{marshal}
 
-\modulesynopsis{Convert Python objects to streams of bytes and back (with
-different constraints).}
+\modulesynopsis{Convert Python objects to streams of bytes and back
+(with different constraints).}
 
 
 This module contains functions that can read and write Python