[chore] readertypeset: normalize string indentation
[chore] readertypeset: normalize string indentation

Same as <https://github.com/koreader/koreader/blob/ece884a368862841fa97b0c8acab429c05621132/frontend/ui/widget/configdialog.lua#L1015-L1019>.

NiLuJe/koreader,mwoz123/koreader,Frenzie/koreader,koreader/koreader,poire-z/koreader,NiLuJe/koreader,poire-z/koreader,koreader/koreader,Markismus/koreader,Frenzie/koreader,mihailim/koreader,Hzj-jie/koreader,pazos/koreader