Merge branch 'td/ref-filter-restore-prefix-iteration' into jch

Commands that list branches and tags (like git branch and git tag)
have been optimized to pass the namespace prefix when initializing
their ref iterator, avoiding a loose-ref scaling regression in
repositories with many unrelated loose references.

* td/ref-filter-restore-prefix-iteration:
  ref-filter: restore prefix-scoped iteration

diff --cc ref-filter.c
Simple merge