scratchdiscussnavlink.user.js

// ==UserScript==
// @name         Scratch Discuss Nav Link
// @namespace    nathanprocks.scratchdiscusslink
// @version      0.2
// @description  try to take over the world!
// @author       nathanprocks
// @match        https://scratch.mit.edu/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var link;
    if (typeof scratch === "undefined") {
        link = document.querySelector("#navigation a[href='/tips']");
    } else {
        link = document.querySelector(".site-nav a[href='/tips']");
    }
    link.href = "/discuss";
    link.textContent = "Discuss";
})();