add info about globals

Hello, I get a 404 when I try to edit https://nightwatchjs.org/guide/writing-tests/using-test-globals.html
May I suggest an update:
to add a global variable to the globals.js file, you can point out that it is not necessary to use the "module.exports" section. Just enter your variable above that section, like regular code:

myGlobal = 3000;