like sometimes people dont realize they messed up until after the fact or if someone accidentally breaks a rule and doesnt realize they formatted it wrong.
like if you are talking about an issue with a server but forgot to write which server its for
or if you tagged a dev but then realized "o crap i wasnt supposed to do that" -
you should be able to go back and remove the offending bits to avoid getting in trouble
This was removed on purpose and there are no plans to bring it back. If you forget to say something important, just make a new post with it, that's what everyone does. If a Moderator sees it they might even merge the two posts into one. As for the other part, think better before posting.