obsfate: improve prune support in _successorsetverb In the prune case, still have markers (at least the prune markers). If we want to be able to return these markers we need the underlying function to support it.

obsfate: rename 'successorsset' to 'sset' in the loop The old name make it too close to 'successorssets', and the shorter name is not ambiguous in the context anyway.

template: use hex node in the obsmarkers used in the obsfate template This was pointed by Yuya and yuya is right.