Since factor 0.98, `fuel-edit-word` has been removed, since
`fuel-edit-word-at-point` has the same behavior when point is not on a symbol.
Also adjust the jump-handler definition.
factor: choose correct name for the `fuel` package
The package is called `fuel`, not `factor-mode`.
This does not make a difference for the layer itself, since it is using the
`site` pseudo-location, and thus never deals with the package files.
Now, any `post-init-fuel` functions defined somewhere else should work
correctly.
factor-layer: add missing refactor command binding, fix initial modes
