Merge branch 'kn/for-each-branch'

Update "git branch" that list existing branches, using the ref-filter API that is shared with "git tag" and "git for-each-ref". * kn/for-each-branch: branch: add '--points-at' option branch.c: use 'ref-filter' APIs branch.c: use 'ref-filter' data structures branch: drop non-commit error reporting branch: move 'current' check down to the presentation layer branch: roll show_detached HEAD into regular ref_list branch: bump get_head_description() to the top branch: refactor width computation