bpo-25910: Link redirections in docs (#1933)

Fixes some redirection links in docs.

Doc/howto/logging.rst

@@ -314,7 +314,7 @@ favourite beverage and carry on.
 If your logging needs are simple, then use the above examples to incorporate
 logging into your own scripts, and if you run into problems or don't
 understand something, please post a question on the comp.lang.python Usenet
-group (available at https://groups.google.com/group/comp.lang.python) and you
+group (available at https://groups.google.com/forum/#!forum/comp.lang.python) and you
 should receive help before too long.
 
 Still here? You can carry on reading the next few sections, which provide a

Doc/howto/pyporting.rst

@@ -433,12 +433,12 @@ to make sure everything functions as expected in both versions of Python.
 .. _Futurize: http://python-future.org/automatic_conversion.html
 .. _importlib: https://docs.python.org/3/library/importlib.html#module-importlib
 .. _importlib2: https://pypi.python.org/pypi/importlib2
-.. _Modernize: https://python-modernize.readthedocs.org/en/latest/
+.. _Modernize: https://python-modernize.readthedocs.io/
 .. _mypy: http://mypy-lang.org/
 .. _Porting to Python 3: http://python3porting.com/
 .. _Pylint: https://pypi.python.org/pypi/pylint
 
-.. _Python 3 Q & A: https://ncoghlan-devs-python-notes.readthedocs.org/en/latest/python3/questions_and_answers.html
+.. _Python 3 Q & A: https://ncoghlan-devs-python-notes.readthedocs.io/en/latest/python3/questions_and_answers.html
 
 .. _pytype: https://github.com/google/pytype
 .. _python-future: http://python-future.org/

Doc/howto/unicode.rst

@@ -214,7 +214,7 @@ difficult reading.  `A chronology <http://www.unicode.org/history/>`_ of the
 origin and development of Unicode is also available on the site.
 
 To help understand the standard, Jukka Korpela has written `an introductory
-guide <https://www.cs.tut.fi/~jkorpela/unicode/guide.html>`_ to reading the
+guide <http://jkorpela.fi/unicode/guide.html>`_ to reading the
 Unicode character tables.
 
 Another `good introductory article <https://www.joelonsoftware.com/2003/10/08/the-absolute-minimum-every-software-developer-absolutely-positively-must-know-about-unicode-and-character-sets-no-excuses/>`_

Doc/howto/urllib2.rst

@@ -403,7 +403,7 @@ fetched, particularly the headers sent by the server. It is currently an
 :class:`http.client.HTTPMessage` instance.
 
 Typical headers include 'Content-length', 'Content-type', and so on. See the
-`Quick Reference to HTTP Headers <https://www.cs.tut.fi/~jkorpela/http.html>`_
+`Quick Reference to HTTP Headers <http://jkorpela.fi/http.html>`_
 for a useful listing of HTTP headers with brief explanations of their meaning
 and use.