ui/key: rename ChordEvent to just Event

Event is like pointer.Event and we don't want the stuttering of
key.KeyEvent.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/app/os_ios.go

@@ -202,7 +202,7 @@ func (w *window) setAnimating(anim bool) {
 }
 
 func (w *window) onKeyCommand(name rune) {
-	w.w.event(key.ChordEvent{
+	w.w.event(key.Event{
 		Name: name,
 	})
 }