Merge branch 'sn/rebase-update-refs-symrefs' into seen

'git rebase --update-refs' has been taught to resolve local branch symrefs to their referents before queuing updates, ensuring aliases of the current branch are skipped and duplicate updates are avoided to prevent failures when branch aliases are present. * sn/rebase-update-refs-symrefs: rebase: guard non-branch symref targets rebase: skip branch symref aliases