I’ve never seen the noexit-yes tag. I don’t think it is nessesery, as it can never have more than 1 exit as its a col-de-sac, as otherwise it wouldn’t be a dead end. The loop at the end of the col-de-sac should have its own way, and tagged with area=yes as well as highway=residential. There is/was a proposal for turning circles to have a tag for nodes also.
this is the wiki page where turning circles were in discussion. There hasn’t been much progress though. Tagging the area at the end with area=yes works, and allows any shape, and therefore this may be why there hasn’t been much progression on this wiki page, as it isn’t much of a problem.