src/vs/editor/contrib/wordOperations/browser/wordOperations.ts/DeleteWordLeft/constructor
class DeleteWordLeft:	constructor() {
		super({
			whitespaceHeuristics: true,
			wordNavigationType: WordNavigationType.WordStart,
			id: 'deleteWordLeft',
			precondition: EditorContextKeys.writable,
			kbOpts: {
				kbExpr: EditorContextKeys.textInputFocus,
				primary: KeyMod.CtrlCmd | KeyCode.Backspace,
				mac: { primary: KeyMod.Alt | KeyCode.Backspace },
				weight: KeybindingWeight.EditorContrib
			}
		});
	}