Update version numbering from 1.6 to 2.0.
diff --git a/Doc/lib/libatexit.tex b/Doc/lib/libatexit.tex
index 077df55..df0cdd4 100644
--- a/Doc/lib/libatexit.tex
+++ b/Doc/lib/libatexit.tex
@@ -6,7 +6,7 @@
 \sectionauthor{Skip Montanaro}{skip@mojam.com}
 \modulesynopsis{Register and execute cleanup functions.}
 
-\versionadded{1.6}
+\versionadded{2.0}
 
 The \module{atexit} module defines a single function to register
 cleanup functions.  Functions thus registered are automatically