Update nightwatch.json - Githubissues

Typings URL: https://github.com/types/npm-nightwatch

Questions (for new typings):

[x] Does the README explain the purpose of the typings and have a link to the JavaScript project?
[x] Do the typings follow the source structure (e.g. index.js <-> index.d.ts)?
[x] Are they external or global modules according to the source (e.g. see README sources)?

Change Summary (for existing typings):

typings / registry