Updating names in test file to match those in test.toml

Author: jagdish-15

exercises/practice/diffie-hellman/diffie-hellman.spec.js

@@ -13,8 +13,8 @@ describe('diffie-hellman', () => {
       new DiffieHellman(10, 13);
     }).toThrow();
   });
-
-  describe('input validation', () => {
+ 
+  describe('private key is greater than 1 and less than p', () => {
     const p = 23;
     const g = 5;
     const diffieHellman = new DiffieHellman(p, g);