docs(quickstart): fix link to styles.css (#2575)

Author: Foxandxss

public/docs/ts/latest/quickstart.jade

@@ -315,7 +315,7 @@ h1#index Step !{step++}: Define the web page that hosts the application
 .callout.is-helpful
   :marked
     For the full set of master styles used by the documentation samples,
-    see [styles.css](https://github.com/angular/angular.io/blob/master/public/docs/_examples/styles.css).
+    see [styles.css](https://github.com/angular/angular.io/blob/master/public/docs/_examples/_boilerplate/styles.css).
 
 .l-main-section#build-and-run
 h1 Step !{step++}: Build and run the application