docs(VmTurnZone): change documentation for VmTurnZone to use term VmTurnZone instead of old NgZone.
docs(VmTurnZone): change documentation for VmTurnZone to use term VmTurnZone instead of old NgZone.

Closes #890

trinarytree/angular.dart,rkirov/angular.dart,winstonewert/angular.dart,SibuStephen/angular.dart,rkirov/angular.dart,winstonewert/angular.dart,winstonewert/angular.dart,trinarytree/angular.dart,hitesh97/angular.dart,ronlobo/angular.dart,rkirov/angular.dart,giovannicandido/angular.dart,hitesh97/angular.dart,hitesh97/angular.dart,giovannicandido/angular.dart,SibuStephen/angular.dart,hitesh97/angular.dart,rkirov/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,giovannicandido/angular.dart,trinarytree/angular.dart,ronlobo/angular.dart,winstonewert/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,trinarytree/angular.dart