Base class for keys events with modifiers.
Contains keys events informations with modifiers support like [code]SHIFT[/code] or [code]ALT[/code]. See [method Node._input].
http://docs.godotengine.org/en/stable/learning/features/inputs/inputevent.html
- State of the Alt modifier.
- State of the Command modifier.
- State of the Ctrl modifier.
- State of the Meta modifier.
- State of the Shift modifier.