New section header style.

Fix up a few synopses.
diff --git a/Doc/lib/librgbimg.tex b/Doc/lib/librgbimg.tex
index d06eb76..5ef0603 100644
--- a/Doc/lib/librgbimg.tex
+++ b/Doc/lib/librgbimg.tex
@@ -1,8 +1,9 @@
-\section{Built-in Module \module{rgbimg}}
+\section{\module{rgbimg} ---
+         Read and write image files in ``SGI RGB'' format.}
 \declaremodule{builtin}{rgbimg}
 
 \modulesynopsis{Read and write image files in ``SGI RGB'' format (the module is
-\emph{not} SGI specific though)!}
+\emph{not} SGI specific though!).}
 
 
 The \module{rgbimg} module allows Python programs to access SGI imglib image