examples(styles): remove duplicate items classes (#2877)
examples(styles): remove duplicate items classes (#2877)

Supersedes #2872 but ensures that we don’t loose `.items li.selected`.
juleskremer/angular.io,Urigo/angular.io,angular/angular.io,angular/angular-cn,juleskremer/angular.io,realappie/angular.io,juleskremer/angular.io,kwalrath/angular.io,realappie/angular.io,realappie/angular.io,rsreimer/angular.io,rsreimer/angular.io,kwalrath/angular.io,IdeaBlade/angular.io,chalin/angular.io,IdeaBlade/angular.io,angular/angular-cn,Urigo/angular.io,onyoon7/angular-ko,kwalrath/angular.io,angular/angular.io,onyoon7/angular-ko,angular/angular-ko,kwalrath/angular.io,angular/angular-cn,realappie/angular.io,onyoon7/angular-ko,angular/angular-cn,chalin/angular.io,angular/angular.io,angular/angular-ko,onyoon7/angular-ko,IdeaBlade/angular.io,rsreimer/angular.io,juleskremer/angular.io,angular/angular-ko,realappie/angular.io,chalin/angular.io,angular/angular-cn,juleskremer/angular.io,rsreimer/angular.io,IdeaBlade/angular.io,chalin/angular.io,chalin/angular.io,kwalrath/angular.io,angular/angular-ko,Urigo/angular.io,Urigo/angular.io,rsreimer/angular.io,Urigo/angular.io,angular/angular.io,angular/angular-ko,IdeaBlade/angular.io,angular/angular.io,onyoon7/angular-ko