Base class for keys events with modifiers.
Contains keys events information with modifiers support like [code]Shift[/code] or [code]Alt[/code]. See [method Node._input].
https://docs.godotengine.org/en/3.1/tutorials/inputs/inputevent.html
State of the [code]Alt[/code] modifier.
State of the [code]Command[/code] modifier.
State of the [code]Ctrl[/code] modifier.
State of the [code]Meta[/code] modifier.
State of the [code]Shift[/code] modifier.