debugstablerange: minor code reformat The content of that list will become more complex as we drop the object so we make sure to have one value per line for clarity.

stablerange: move the subrangesclosure inside the module This seems more suitable and open the way to simple update of how we build things without too much impact outside the module. The debug command is still in the 'obsdiscovery' module because it also deal to obshash and I'm not sure of were this should live yet.