Add 'Learn TypeScript in Y Minutes' (#3862)

free-programming-books.md

@@ -2700,6 +2700,7 @@ Kerridge (PDF) (email address *requested*, not required)
 
 ### TypeScript
 
+* [Learn TypeScript in Y Minutes](https://learnxinyminutes.com/docs/typescript/)
 * [TypeScript Accelerated](https://accelerated.amimetic.co.uk) - James Porter
 * [TypeScript Deep Dive](https://basarat.gitbooks.io/typescript/)
 * [TypeScript for C# Programmers](http://www.infoq.com/minibooks/typescript-c-sharp-programmers)