Added note that this module was added in Python 2.1.

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