docs(guide/introduction): fix grammar style

Changed "you would currently have to write" to "you would otherwise have to write".

Seems to make more sense this way since "currently" presupposes that someone new
to Angular would be coming from a different paradigm, which they may or may not be.

Closes angular#9428

Author: bijanbwb

docs/content/guide/introduction.ngdoc

@@ -9,7 +9,7 @@
 AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template
 language and lets you extend HTML's syntax to express your application's components clearly and
 succinctly. Angular's data binding and dependency injection eliminate much of the code you
-currently have to write. And it all happens within the browser, making it
+would otherwise have to write. And it all happens within the browser, making it
 an ideal partner with any server technology.
 
 Angular is what HTML would have been had it been designed for applications. HTML is a great