Change behaviour of Note input shortcuts

Shortcuts for the note input methods (i.e. re-pitch, Step-Time) should act as toggle switches.
When a shortcut is used, it will change to the associated input method. It will also change to Note Input mode if the currrent state is Normal. If it is used again while still in Note input it has no effect.
It is proposed, that when used in Note Input mode, it should return the state to Normal.

See also discussion here: https://musescore.org/en/node/277577