When `EDITOR` or `VISUAL` are not set, we fallback to the most common
editors. It turns out many users don't have these variables set.
We also check if an editor has been configured with `git`.
This adds the ability to the git-remote-helper to open and update
patches via a `git push` to the magic ref `refs/patches` and
`refs/heads/patches/<patch-id>`.
The main change is that we had to move away from offering the `connect`
capability in the remote helper, to offering `push` and `fetch`
individually.
To get a feel for how this works, see the `rad-patch-via-push.md`
example.
cloudhead
Alexis Sellier