`git-update-branch`: drive-by rebase local branchs
improve `git graph`

h/t Seb
switch `gln` back to `g lg`
add some git log / files helpers
add “(no branch)” as an option to `gb`
add link-only option to `mk-git`
clean up arg parsing in `mk`

TODO: don’t remember what this script was for
rename misnamed `git-root`
quote args in `git-relpath`
add `git-root` helper to print git root dir
helper to print last “good” SHA during bisection