Re: [PATCH 2/6] builtin/clone: propagate ref storage format to submodules

Patrick Steinhardt [off-list ref] writes:

When recursively cloning a repository with a non-default ref storage
format, e.g. by passing the `--ref-format=` option, then only the
top-level repository will end up will end up using that ref storage
format. All recursively cloned submodules will instead use the default
format. While mixed-format constellations are expected to work alright,
the outcome still is somewhat surprising as we have essentially ignored
the user's request.

Fix this by propagating the requested ref format to cloned submodules.

Makes sense.