generate new test that did already exist & update all module snippets with declaration

test/lcm/lcm.js

@@ -1,4 +1,4 @@
-module.exports = (...arr) => {
+module.exports = lcm = (...arr) => {
 const gcd = (x, y) => (!y ? x : gcd(y, x % y));
 const _lcm = (x, y) => x * y / gcd(x, y);
 return [...arr].reduce((a, b) => _lcm(a, b));