Remove dead link to "The Standard Python Library" (#5240)

* Remove dead link to "The Standard Python Library"

The link to the book "The Standard Python Library" hosted on effbot.org is dead, and I could not find another source that legally hosts that book.

* Update free-programming-books.md

The link to the book "The Standard Python Library" hosted on effbot.org is dead:

http://effbot.org/librarybook/

This change updates it to the one at archive.org.

books/free-programming-books.md

@@ -2459,7 +2459,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [The Little Book of Python Anti-Patterns](http://docs.quantifiedcode.com/python-anti-patterns/) ([Source](https://github.com/quantifiedcode/python-anti-patterns))
 * [The Programming Historian](http://niche-canada.org/research/niche-digital-infrastructure-project/the-programming-historian/) - William J. Turkel, Adam Crymble and Alan MacEachern
 * [The Python GTK+ 3 Tutorial](http://python-gtk-3-tutorial.readthedocs.org/en/latest/)
-* [The Standard Python Library](http://effbot.org/librarybook/) - Fredrik Lundh
+* [The Standard Python Library](https://web.archive.org/web/20200626001242/http://effbot.org/librarybook/) - Fredrik Lundh
 * [Think Complexity](https://greenteapress.com/wp/think-complexity-2e/) - Allen B. Downey (2nd Edition) (PDF, HTML)
 * [Think DSP - Digital Signal Processing in Python](https://greenteapress.com/wp/think-dsp/) - Allen B. Downey (PDF, HTML)
 * [Tiny Python 3.6 Notebook](https://github.com/mattharrison/Tiny-Python-3.6-Notebook) - Matt Harrison (3.6)