src/vs/platform/theme/common/themeService.ts/modify
	export function modify(icon: ThemeIcon, modifier: 'disabled' | 'spin' | undefined): ThemeIcon {
		let id = icon.id;
		const tildeIndex = id.lastIndexOf('~');
		if (tildeIndex !== -1) {
			id = id.substring(0, tildeIndex);
		}
		if (modifier) {
			id = `${id}~${modifier}`;
		}
		return { id };
	}