Follow-up from #31718.
This ticket proposes to deprecate list_of_subsets (note - no other methods in sage.manifolds follow this naming scheme) in favor of a new method subset_family, which prints in a more compact way, is hashable, and is sorted by name too.
We also add superset_family (previously the set of supersets was not exposed by a method).
We also add open_superset_family (to complement open_superset added in #31677).
Depends on #31718
Depends on #31677
CC:  @egourgoulhon @mjungmath @tscrim
Component: manifolds
Author: Matthias Koeppe
Branch/Commit: 2b47b1b
Reviewer: Eric Gourgoulhon
Issue created by migration from https://trac.sagemath.org/ticket/31727