When composing an email with mu4e, mu4e-walk allows for moving
around email addresses in the header with just one key stroke:

- Move email address "vertically" between address fields
- Move email address "horizontally" within an address field
- Also works with regions

The most important functions and default keybindings are:

| Function        | Keybinding  |
|-----------------+-------------|
| mu4e-walk-up    | M-<up>      |
| mu4e-walk-down  | M-<down>    |
| mu4e-walk-left  | M-<left>    |
| mu4e-walk-right | M-<right>   |

Installation note: This package depends on mu4e which must be installed
separately from package.el.