docs(upgrade): rename Angular 2 to Angular (#3169)
docs(upgrade): rename Angular 2 to Angular (#3169)


IdeaBlade/angular.io,chalin/angular.io,angular/angular.io,angular/angular-cn,IdeaBlade/angular.io,angular/angular.io,juleskremer/angular.io,angular/angular.io,angular/angular-ko,onyoon7/angular-ko,angular/angular-cn,chalin/angular.io,angular/angular-ko,onyoon7/angular-ko,chalin/angular.io,angular/angular.io,angular/angular.io,angular/angular-cn,IdeaBlade/angular.io,angular/angular-cn,IdeaBlade/angular.io,angular/angular-ko,angular/angular-cn,juleskremer/angular.io,juleskremer/angular.io,onyoon7/angular-ko,chalin/angular.io,juleskremer/angular.io,onyoon7/angular-ko,angular/angular-ko,onyoon7/angular-ko,juleskremer/angular.io,angular/angular-ko,IdeaBlade/angular.io,chalin/angular.io