Explain *why* the copytree() implementation is presented as the
example!
diff --git a/Doc/lib/libshutil.tex b/Doc/lib/libshutil.tex
index f55c517..1f3f6d8 100644
--- a/Doc/lib/libshutil.tex
+++ b/Doc/lib/libshutil.tex
@@ -81,7 +81,8 @@
 \subsection{Example \label{shutil-example}}
 
 This example is the implementation of the \function{copytree()}
-function, described above, with the docstring omitted.
+function, described above, with the docstring omitted.  It
+demonstrates many of the other functions provided by this module.
 
 \begin{verbatim}
 def copytree(src, dst, symlinks=0):