Well, in principle both mean exactly the same thing, so I don't have strong opinion on this. I probably use them interchangeably anyway. Well, it's auto, so we don't care what type it is... So based on that I would say no need to make a commit. Other parts of KDE codebase also don't have unified style here. Just checked kwin, it has both auto and auto *
Just note that e.g. in ranged based for loop we usually want for (const auto & a : ... ). There const and & actually make a difference unlike here.