Re: [PATCH 4/4] builtin/remote: only iterate through refs that are to be renamed

Patrick Steinhardt [off-list ref] writes:

When renaming a remote we also need to rename all references
accordingly. But while we only need to rename references that are
contained in the "refs/remotes/$OLDNAME/" namespace, we end up using
`refs_for_each_rawref()` that iterates through _all_ references. We know
to exit early in the callback in case we see an irrelevant reference,
but ultimately this is still a waste of compute as we knowingly iterate
through references that we won't ever care about.

Very true.  Even if we guarantee that callbacks are fed references in
lexicographic order, that would only allow us to stop iterationg
when we see an irrelevant one", and still would force us to skip
over all the irrelevant ones until we see the first one in scope.

It makes perfect sense to give us a way to say "iterate only in this
subhierarchy" like this step does.

Nice.