Improve documentation for async.seq
Improve documentation for async.seq

- seq requires the last argument to be a function
- seq short-circuits on errors which means using handleError is redundant

bjlxj2008/async,r14r/fork_javascript_async,Qix-/async,LeoYao/async,FrankSunnyvale/async,lanffy/async,evdevgit/async,andyburke/antisync,lanffy/async,llwanghong/async,pandoraui/async,moander/async,sjclijie/async,xiebaochun/async,ecasilla/async,KnottedRain/async,jamesjnadeau/async,XM-Right/async,kolomiichenko/async,Zhang/async,renruixi/async,beni55/async,ariesnah/async,RickyDan/async,suguru03/async,tjwudi/async,megawac/async,ezubarev/async,llwanghong/async,chaddm/async,chaddm/async,Zhang/async,carck/async,youprofit/async,navyxie/async,andalm/async,Kikobeats/async,gypsydave5/async,justincy/async,navyxie/async,SaiNadh001/async,beni55/async,wrenth04/async,jnordberg/async,ariesnah/async,hargasinski/async,scq000/async,KnottedRain/async,arigo-software/async,wushuyi/async,abhishekgahlot/async,kolomiichenko/async,bjlxj2008/async,DaAwesomeP/async,ArcadiusK/async,garysye/async,abhishekgahlot/async,caolan/async,DanieleTassone/async,lonely8rain/async,rborisov/async,Kikobeats/async,gypsydave5/async,zhhb/async,zhakui/async,Segeon-Kim/async,rlugojr/async,pandoraui/async,JulianVolodia/async,hargasinski/async,ibakaidov/async,haggholm/async,rborisov/async,haggholm/async,jnordberg/async,wushuyi/async,r14r-work/fork_javascript_async,DDunc/async,Connectlegendary/async,ecasilla/async,DaAwesomeP/async,Segeon-Kim/async,rlugojr/async,ezubarev/async,r14r/fork_javascript_async,andyburke/antisync,megawac/async,Connectlegendary/async,DDunc/async,DanieleTassone/async,pandeysoni/async,evdevgit/async,zhakui/async,modulexcite/async,zhhb/async,jaruba/async,moander/async,Qix-/async,lonely8rain/async,ArcadiusK/async,pandeysoni/async,markyen/async,garysye/async,caolan/async,imjerrybao/async,Segeon-Kim/async,LeoYao/async,youprofit/async,tjwudi/async,suguru03/async,arigo-software/async,sjclijie/async,steverobb/async,XM-Right/async,FrankSunnyvale/async,mcanthony/async,andalm/async,imjerrybao/async,scq000/async,xiebaochun/async,RickyDan/async,r14r-work/fork_javascript_async,jamesjnadeau/async,wrenth04/async,renruixi/async,ibakaidov/async,justincy/async,SaiNadh001/async,carck/async,JulianVolodia/async,steverobb/async,markyen/async,mcanthony/async,modulexcite/async,jaruba/async