Add and fix Python resources, check_urls=free-programming-books.md (#5111)

Co-authored-by: Eric Hellman <eric@hellman.net>

free-programming-books.md

@@ -2410,8 +2410,8 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Python 3 Official Documentation](https://docs.python.org/3/download.html) (PDF, EPUB, HTML, TEXT) (3.x)
 * [Python 3 Tutorial](https://github.com/Akuli/python-tutorial)
 * [Python Data Science Handbook](https://jakevdp.github.io/PythonDataScienceHandbook) - Jake VanderPlas (HTML, Jupyter Notebooks)
-* [Python for Everybody Exploring Data Using Python 3](http://py4e.com/book.php) - Charles Severance (PDF, EPUB, HTML)
-  * [Python for Informatics: Exploring Information](http://www.pythonlearn.com/book.php) (2.7.5)
+* [Python for Everybody](http://py4e.com/book) - Charles Russell Severance (PDF, EPUB, HTML) (3.x)
+* [Python for Informatics: Exploring Information](http://www.pythonlearn.com/book.php) - Charles Russell Severance (2.7.5)
 * [Python for you and me](http://pymbook.readthedocs.org/en/latest/) (2.7.3)
 * [Python for you and me](http://pymbook.readthedocs.org/en/py3/) (3.x)
 * [Python Idioms](http://safehammad.com/downloads/python-idioms-2014-01-16.pdf) (PDF)