I don't like the built-in one.
It now supports worktrees correctly (or at least I can't figure out which issue I used to have with it...). As a bonus, it also supports showing the correct branch for an `oil` buffer. This reverts commit 481d5f6f53.
481d5f6f53
I want to tighten the API of this function a little bit, so let's be more specific.
Consolidating all modules under the same path, to clear out the top-level directory.
