pub fn split(chord: &str) -> Result<(Vec<&str>, &str), ChordError>Expand description
Split a chord into its modifiers and its final key: cmd+shift+s →
(["cmd", "shift"], "s").
Whitespace around the parts is tolerated because chords are
hand-written in flow files, where cmd + s is a reasonable thing to
type. An empty chord is an error rather than a no-op: a step that
presses nothing is a typo, not an instruction.