[Listbox] Modifier keys keyboard interactions

[samaraoliveiram]

• Shift + Down Arrow (Optional): Moves focus to and toggles the selected state of the next option.
• Shift + Up Arrow (Optional): Moves focus to and toggles the selected state of the previous option.
• Shift + Space (Optional): Selects contiguous items from the most recently selected item to the focused item.
• Control + Shift + Home (Optional): Selects the focused option and all options up to the first option. Optionally, moves focus to the first option.
• Control + Shift + End (Optional): Selects the focused option and all options down to the last option. Optionally, moves focus to the last option.
• Control + A (Optional): Selects all options in the list. Optionally, if all options are selected, it may also unselect all options.