New section header style.

Fix up a few synopses.
diff --git a/Doc/lib/libtraceback.tex b/Doc/lib/libtraceback.tex
index 29c8ac6..e2a7e07 100644
--- a/Doc/lib/libtraceback.tex
+++ b/Doc/lib/libtraceback.tex
@@ -1,4 +1,5 @@
-\section{Standard Module \module{traceback}}
+\section{\module{traceback} ---
+         Print or retrieve a stack traceback.}
 \declaremodule{standard}{traceback}
 
 \modulesynopsis{Print or retrieve a stack traceback.}