Change KeyComboAction.get to return option(Action.t) instead of Action.t
Change KeyComboAction.get to return option(Action.t) instead of Action.t

The function now returns None instead of raisining an exception.

This commit will not build, since there are still changes in ActionPanel.re and UHCode.re that need to be made to accomodate this change.

hazelgrove/hazel,hazelgrove/hazel,hazelgrove/hazel