Added note that the atexit module was added for Python 1.6.
diff --git a/Doc/lib/libatexit.tex b/Doc/lib/libatexit.tex
index 9d0b48c..077df55 100644
--- a/Doc/lib/libatexit.tex
+++ b/Doc/lib/libatexit.tex
@@ -6,6 +6,8 @@
\sectionauthor{Skip Montanaro}{skip@mojam.com}
\modulesynopsis{Register and execute cleanup functions.}
+\versionadded{1.6}
+
The \module{atexit} module defines a single function to register
cleanup functions. Functions thus registered are automatically
executed upon normal interpreter termination.