improve description for ArrayStack introduction
improve description for ArrayStack introduction

RussellSpitzer/snakeyaml,cuizhennan/snakeyaml,ilantoren/snakeyaml,thinkofdeath/snakeyaml,Akkrite/snakeyaml,mapiman/snakeyaml,UcasRichard/snakeyaml,AssafMashiah/assafmashiah-yaml,youxinren/snakeyaml,nxbdi/snakeyaml,umeding/snakeyaml,yeison/snakeyaml,votinhthieugia/snakeyaml,Mause/snakeyaml,jeremypepper/snakeyaml,marcuskara/snakeyaml,yishenggudou/snakeyaml,yskumar007/snakeyaml,Fighter777/snakeyaml,joy32812/snakeyaml,SorinS/snakeyaml,virustotalop/snakeyaml,ldh0826/snakeyaml,mc-nekoneko/snakeyaml