Display plain text message indent as vertical bar: Closes #4643
Display plain text message indent as vertical bar: Closes #4643

AtticHacker/geary,martinra/geary,rschroll/geary,aatishnn/geary,aatishnn/geary,tshikaboom/geary,tshikaboom/geary,AtticHacker/geary,emersion/geary,githubnemo/geary,orlandosanchez/geary,didrocks/geary,glebihan/geary,glebihan/geary,kyoushuu/geary,jimbonator/geary,mjog/geary,orlandosanchez/geary,orlandosanchez/geary,jimbonator/geary,mjog/geary,mpdeimos/geary,emersion/geary,martinra/geary,dominickm/Geary,githubnemo/geary,tshikaboom/geary,robol/geary,kpiwko/geary,githubnemo/geary,jimbonator/geary,glebihan/geary,emersion/geary,martinra/geary,MohamedIM/geary-unofficial,abn/geary,rschroll/geary,geekvigilante/geary,robol/geary,mjog/geary,kyoushuu/geary,robol/geary,dominickm/Geary,aatishnn/geary,AtticHacker/geary