docs(misc/started): update Twitter handle (@angularjs --> @angular)

Closes #15671

Author: Chris

docs/content/misc/started.ngdoc

@@ -32,7 +32,7 @@ tutorials.
 ## Subscribe
 
 * Subscribe to the [mailing list](http://groups.google.com/forum/?fromgroups#!forum/angular).  Ask questions here!
-* Follow us on [Twitter](https://twitter.com/intent/follow?original_referer=http%3A%2F%2Fangularjs.org%2F&region=follow_link&screen_name=angularjs&source=followbutton&variant=2.0)
+* Follow us on [Twitter](https://twitter.com/intent/follow?original_referer=http%3A%2F%2Fangularjs.org%2F&region=follow_link&screen_name=angular&source=followbutton&variant=2.0)
 * Add us to your circles on [Google+](https://plus.google.com/110323587230527980117/posts)
 
 ## Read more