Of course, James Mangold has not always eschewed superhero post-credits scenes.
He was responsible for a tease at the end of The Wolverine that technically paid off in X-Men: Days of Future Past but was ultimately mostly discarded by never explaining the resurrection of Charles Xavier (Patrick Stewart) after X-Men: The Last Stand, or how Wolverine (Hugh Jackman) got one of his adamantium claws back.
Still, looking at what he has to say about these sequences, it arguably seems safe to assume that he won’t do another one anytime soon.
There are others who would argue that post-credit scenes keep people in their seats while the names of all the hard-working people who actually labored on the film flash by, but James Mangold doesn’t seem to see it that way.