add some documentation for 2to3
diff --git a/Doc/library/development.rst b/Doc/library/development.rst
index ff4cb00..8cd3d0c 100644
--- a/Doc/library/development.rst
+++ b/Doc/library/development.rst
@@ -9,7 +9,8 @@
:mod:`pydoc` module takes a module and generates documentation based on the
module's contents. The :mod:`doctest` and :mod:`unittest` modules contains
frameworks for writing unit tests that automatically exercise code and verify
-that the expected output is produced.
+that the expected output is produced. :program:`2to3` can translate Python 2.x
+source code into valid Python 3.x code.
The list of modules described in this chapter is:
@@ -19,4 +20,5 @@
pydoc.rst
doctest.rst
unittest.rst
+ 2to3.rst
test.rst