Added note that this module was added in Python 2.1.
diff --git a/Doc/lib/libxreadlines.tex b/Doc/lib/libxreadlines.tex
index 0285f03..d824fc3 100644
--- a/Doc/lib/libxreadlines.tex
+++ b/Doc/lib/libxreadlines.tex
@@ -4,6 +4,9 @@
\declaremodule{extension}{xreadlines}
\modulesynopsis{Efficient iteration over the lines of a file.}
+\versionadded{2.1}
+
+
This module defines a new object type which can efficiently iterate
over the lines of a file. An xreadlines object is a sequence type
which implements simple in-order indexing beginning at \code{0}, as