Merge pull request #1062 from lucasalavapena/patch-1

Fixed Pro Python link from unused domain to seller

Author: dbader

docs/intro/learning.rst

@@ -236,7 +236,7 @@ This book is for intermediate to advanced Python programmers who are looking to
 understand how and why Python works the way it does and how they can take their
 code to the next level.
 
-    `Pro Python <http://propython.com>`_
+    `Pro Python <https://www.apress.com/gp/book/9781430227571>`_
 
 
 Expert Python Programming