Updated a bunch of hyperlinks in documentation

docs/internals/contributing/localizing.txt

@@ -61,6 +61,6 @@ Django source tree, as for any code change:
   ``Translations``, and attach the patch to it.
 
 .. _Transifex: https://www.transifex.com/
-.. _Django i18n mailing list: http://groups.google.com/group/django-i18n/
+.. _Django i18n mailing list: /https://groups.google.com/d/forum/django-i18n
 .. _Django project page: https://www.transifex.com/projects/p/django-core/
-.. _Transifex User Guide: http://help.transifex.com/
+.. _Transifex User Guide: http://support.transifex.com/

docs/internals/contributing/writing-code/coding-style.txt

@@ -213,4 +213,4 @@ Miscellaneous
   change to the ``AUTHORS`` file in your patch if you make more than a
   single trivial change.
 
-.. _flake8: http://pypi.python.org/pypi/flake8
+.. _flake8: https://pypi.python.org/pypi/flake8

docs/internals/contributing/writing-code/unit-tests.txt

@@ -187,11 +187,11 @@ associated tests will be skipped.
 .. _Pillow: https://pypi.python.org/pypi/Pillow/
 .. _PyYAML: http://pyyaml.org/wiki/PyYAML
 .. _pytz: https://pypi.python.org/pypi/pytz/
-.. _setuptools: http://pypi.python.org/pypi/setuptools/
+.. _setuptools: https://pypi.python.org/pypi/setuptools/
 .. _memcached: http://memcached.org/
 .. _gettext: http://www.gnu.org/software/gettext/manual/gettext.html
-.. _selenium: http://pypi.python.org/pypi/selenium
-.. _pip requirements files: http://www.pip-installer.org/en/latest/requirements.html
+.. _selenium: https://pypi.python.org/pypi/selenium
+.. _pip requirements files: http://www.pip-installer.org/en/latest/cookbook.html#requirements-files
 
 Code coverage
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