Issue #2486019 by mpdonadio, pfrenssen, webflo, michielnugter, maris.abols, ivanjaros, hauruck, MickeA, Jo Fitzgerald, mian3010, iMiksu: Wrong validation messages in Datelist::validateDatelist()

Issue #2541252 by HOG, finnsky, LewisNyman, nlisgo, saki007ster, alvar0hurtad0, maris.abols, pjbaert, bruvers, emma.maria, ti2m: Replace the .region-content ul/ol selector with text-formatted