Fix broken link in Why React post

Author: zpao

docs/_posts/2013-06-05-why-react.md

@@ -31,7 +31,7 @@ see as an advantage over templates for a few reasons:
   **no manual string concatenation** and therefore less surface area for XSS
   vulnerabilities.
 
-We've also created [JSX](facebook.github.io/react/docs/syntax.html), an optional
+We've also created [JSX](http://facebook.github.io/react/docs/syntax.html), an optional
 syntax extension, in case you prefer the readability of HTML to raw JavaScript.
 
 ## Reactive updates are dead simple.