isLink
import { isLink } from "https://github.gh-proxy.cn/raw.githubusercontent.com/baetheus/fun/main/free.ts";Check if a Free structure is a Link.
@example
import { isLink, node, link } from "./free.ts";
const single = node(1);
const combined = link(node(1), node(2));
console.log(isLink(single)); // false
console.log(isLink(combined)); // true