Changes

API: fix the documentation of hwloc_cpuset_from/to_nodeset()
It was outdated since v2+ topologies always had NUMA nodes, and some
clarification were needed anyway.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
(cherry picked from commit ea991c6186d6325159b2142ec50b7561c94eca5b)