I'm not sure if there's an easy way to do this, but if you need a list of all the special key names, there's a comment in the TypeScript API browser in Sup.Input that says:
// Valid key names (based on window.KeyEvent.DOM_VK_*):
// CANCEL, HELP, BACK_SPACE, TAB, CLEAR, RETURN, SHIFT, CONTROL, ALT,
// PAUSE, CAPS_LOCK, ESCAPE, SPACE, PAGE_UP, PAGE_DOWN, END, HOME,
// LEFT, UP, RIGHT, DOWN, PRINTSCREEN, INSERT, DELETE,
// 0 to 9, SEMICOLON, EQUALS, A to Z,
// CONTEXT_MENU, NUMPAD0 to NUMPAD9,
// MULTIPLY, ADD, SEPARATOR, SUBTRACT, DECIMAL, DIVIDE,
// F1 to F24, NUM_LOCK, SCROLL_LOCK, COMMA, PERIOD, SLASH, BACK_QUOTE,
// OPEN_BRACKET, BACK_SLASH, CLOSE_BRACKET, QUOTE, META
//
// Additionnally, ANY will return true for any key
// and NONE will return true for no keys