Reduce complexity in SymbolProc
Reduce complexity in SymbolProc

Split `on_block` into smaller methods and clarify variable naming a
bit.

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