feat(util): add array.Append helper
feat(util): add array.Append helper

frankyifei/koreader,NiLuJe/koreader,NiLuJe/koreader,poire-z/koreader,chihyang/koreader,mihailim/koreader,robert00s/koreader,pazos/koreader,poire-z/koreader,NickSavage/koreader,Frenzie/koreader,koreader/koreader,lgeek/koreader,koreader/koreader,Markismus/koreader,Hzj-jie/koreader,mwoz123/koreader,apletnev/koreader,Frenzie/koreader,houqp/koreader