Fix misformatted list item on courses (EbookFoundation#2611)

Fix a small mistake that causes errors in display of the courses list.

Author: marcolussetti

free-courses-en.md

@@ -119,7 +119,7 @@
 ### Data Science
 
 * [Introduction to Python for Data Science](https://www.edx.org/course/introduction-python-data-science-microsoft-dat208x-3)
-  *[The Analytics Edge](https://www.edx.org/course/analytics-edge-mitx-15-071x-3)
+* [The Analytics Edge](https://www.edx.org/course/analytics-edge-mitx-15-071x-3)
 
 
 ### Databases