Change PEP 8 and pep8 RST references.

CONTRIBUTING.rst

@@ -13,13 +13,13 @@ an unrelated area of the code).
 Code Style
 ----------
 
-Code *must* be compliant with `PEP8`_.Use the latest version of `pep8pypi`_ or
+Code *must* be compliant with `PEP 8`_. Use the latest version of `pep8`_ or
 `flake8`_ to catch issues.
 
 Git commit messages should include `a summary and proper line wrapping`_.
 
-.. _PEP8: http://www.python.org/dev/peps/pep-0008/
-.. _pep8pypi: https://pypi.python.org/pypi/pep8
+.. _PEP 8: http://www.python.org/dev/peps/pep-0008/
+.. _pep8: https://pypi.python.org/pypi/pep8
 .. _flake8: https://pypi.python.org/pypi/flake8
 .. _a summary and proper line wrapping: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html