Fix lots of broken links in the docs, found by Sphinx' external link checker.
diff --git a/Doc/library/tkinter.rst b/Doc/library/tkinter.rst
index 71b71e2..d393341 100644
--- a/Doc/library/tkinter.rst
+++ b/Doc/library/tkinter.rst
@@ -21,7 +21,7 @@
`An Introduction to Tkinter <http://www.pythonware.com/library/an-introduction-to-tkinter.htm>`_
Fredrik Lundh's on-line reference material.
- `Tkinter reference: a GUI for Python <http://www.nmt.edu/tcc/help/pubs/lang.html>`_
+ `Tkinter reference: a GUI for Python <http://infohost.nmt.edu/tcc/help/pubs/lang.html>`_
On-line reference material.
`Tkinter for JPython <http://jtkinter.sourceforge.net>`_