Reduce complexity in TrailingComma mixin
Reduce complexity in TrailingComma mixin

Split `check` into smaller methods.

b-t-g/rubocop,maxjacobson/rubocop,alexdowad/rubocop,legendetm/rubocop,jfelchner/rubocop,b-t-g/rubocop,legendetm/rubocop,mikegee/rubocop,bankair/rubocop,jmks/rubocop,backus/rubocop,akihiro17/rubocop,bbatsov/rubocop,mikegee/rubocop,mclark/rubocop,urbanautomaton/rubocop,backus/rubocop,lumeet/rubocop,savef/rubocop,urbanautomaton/rubocop,lumeet/rubocop,jmks/rubocop,smakagon/rubocop,meganemura/rubocop,lucasuyezu/rubocop,jfelchner/rubocop,lucasuyezu/rubocop,palkan/rubocop,panthomakos/rubocop,iGEL/rubocop,sinsoku/rubocop,bquorning/rubocop,Drenmi/rubocop,tdeo/rubocop,alexdowad/rubocop,alexcstark/rubocop,akihiro17/rubocop,sue445/rubocop,pocke/rubocop,petehamilton/rubocop,tdeo/rubocop,dreyks/rubocop,deivid-rodriguez/rubocop,jmks/rubocop,hanumakanthvvn/rubocop,petehamilton/rubocop,rrosenblum/rubocop,deivid-rodriguez/rubocop,vergenzt/rubocop,bquorning/rubocop,ilansh/rubocop,haziqhafizuddin/rubocop,alexcstark/rubocop,palkan/rubocop,dreyks/rubocop,tejasbubane/rubocop,panthomakos/rubocop,tejasbubane/rubocop,meganemura/rubocop,tejasbubane/rubocop,tdeo/rubocop,maxjacobson/rubocop,rtlechow/rubocop,Drenmi/rubocop,sue445/rubocop,sue445/rubocop,petehamilton/rubocop,panthomakos/rubocop,mikegee/rubocop,melch/rubocop,sinsoku/rubocop,smakagon/rubocop,rrosenblum/rubocop,ilansh/rubocop,savef/rubocop,maxjacobson/rubocop,iGEL/rubocop,scottmatthewman/rubocop,NobodysNightmare/rubocop,bbatsov/rubocop,meganemura/rubocop,melch/rubocop,vergenzt/rubocop,akihiro17/rubocop,rtlechow/rubocop,vergenzt/rubocop,scottmatthewman/rubocop,NobodysNightmare/rubocop,hanumakanthvvn/rubocop,pocke/rubocop,mclark/rubocop,deivid-rodriguez/rubocop,haziqhafizuddin/rubocop,bankair/rubocop,jfelchner/rubocop,rrosenblum/rubocop,bquorning/rubocop,palkan/rubocop