Ref T13659. I don't think this name actually matters since Mercurial doesn't care what the extension name is, but be a little more consistent.
- Maniphest Tasks
- T13659: `arc land` may fail with missing rebase extension
- rARC82016c00e132: Name extension as "arc-hg", not "arg-hg"
Ran "arc land ..." and saw it run "arc-hg" commands. There's no behavioral change here: Mercurial loads the extension and runs fine no matter what name we provide.