docs(quickstart): fix link to styles.css

[Foxandxss]

Fixes #2571

[killrazor]

This fix needed to be a few other places.

All of these should be https://github.com/angular/angular.io/blob/master/public/docs/_examples/boilerplate/styles.css

• public/docs/js/latest/quickstart.jade:see [styles.css](https://github.com/angular/angular.io/blob/master/public/docs/_examples/styles.css).
• public/docs/_examples/quickstart/js/styles.1.css:* See https://github.com/angular/angular.io/blob/master/public/docs/_examples/styles.css
• public/docs/ts/_cache/quickstart.jade:see [styles.css](https://github.com/angular/angular.io/blob/master/public/docs/_examples/styles.css).

I'm not sure what this link should be but it 404s

• public/docs/ts/_cache/tutorial/toh-pt5.jade:- var styles_css = 'https://raw.githubusercontent.com/angular/angular.io/master/public/docs/_examples/styles.css'

[chalin]

@killrazor - thanks for the reminder.
Dart issue tracker: #2753.
@Foxandxss - I'll leave it up to you as to whether you want to reopen #2571 to track the JS changes or not.