src/vs/base/browser/ui/toggle/toggle.ts/Toggle/setIcon
class Toggle:	setIcon(icon: CSSIcon | undefined): void {
		if (this._icon) {
			this.domNode.classList.remove(...CSSIcon.asClassNameArray(this._icon));
		}
		this._icon = icon;
		if (this._icon) {
			this.domNode.classList.add(...CSSIcon.asClassNameArray(this._icon));
		}
	}