Update comments about the performance of xrange().
diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index 4372ec1..a104d85 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -884,8 +884,8 @@
size of the range it represents. There are no consistent performance
advantages.
-XRange objects have very little behavior: they only support indexing
-and the \function{len()} function.
+XRange objects have very little behavior: they only support indexing,
+iteration, and the \function{len()} function.
\subsubsection{Mutable Sequence Types \label{typesseq-mutable}}