Add note that difflib was added in Python 2.1.
diff --git a/Doc/lib/libdifflib.tex b/Doc/lib/libdifflib.tex
index aa09a9d..0c35d60 100644
--- a/Doc/lib/libdifflib.tex
+++ b/Doc/lib/libdifflib.tex
@@ -7,6 +7,9 @@
 \sectionauthor{Tim Peters}{tim.one@home.com}
 % LaTeXification by Fred L. Drake, Jr. <fdrake@acm.org>.
 
+\versionadded{2.1}
+
+
 \begin{funcdesc}{get_close_matches}{word, possibilities\optional{,
                  n\optional{, cutoff}}}
   Return a list of the best ``good enough'' matches.  \var{word} is a