[update] Update vanillajs.md
[update] Update vanillajs.md

Updated typos
hamzawi06/docs,sandrinodimattia/docs,hamzawi06/docs,jeffreylees/docs,Annyv2/docs,jeffreylees/docs,yvonnewilson/docs,jeffreylees/docs,Catografix/docs,auth0/docs,khorne3/docs,Annyv2/docs,Annyv2/docs,miparnisari/docs,auth0/docs,khorne3/docs,hamzawi06/docs,sandrinodimattia/docs,Catografix/docs,sandrinodimattia/docs,Catografix/docs,khorne3/docs,yvonnewilson/docs,yvonnewilson/docs,auth0/docs