docs(misc): fix typo in "getting started" docs

changed "building and application" to "building an application"

Closes angular#6156

Author: asif22

docs/content/misc/started.ngdoc

@@ -7,7 +7,7 @@ becoming an Angular expert.
 
 1. Read the {@link guide/concepts conceptual overview}.<br/>Understand Angular's vocabulary and how all the Angular
    components work together.
-1. Do the {@link tutorial/ AngularJS Tutorial}.<br/>Walk end-to-end through building and application complete with tests
+1. Do the {@link tutorial/ AngularJS Tutorial}.<br/>Walk end-to-end through building an application complete with tests
    on top of a node.js web server.  Covers every major AngularJS feature and show you how to set up your development
    environment.
 1. Download or clone the {@link https://github.com/angular/angular-seed Seed App project template}.<br/>Gives you a