CAN's edit command should load the named note into the scratchfile¶
When a valid note name is passed to the edit command, the named note should be loaded for editing into the scratchfile.
When the note is inserted, other contents of the scratchfile should remain untouched beneath the fold, to avoid losing information and to make a stack-based approach to note editing possible.
The edit-note handler should listen for the COMMAND_EDIT event in order to know when to do this, and the NOTE_EXISTENCE event should be emitted so other systems know a new note has been loaded into the scratchfile.