I updated nearly all of the help docs to bring them up-to-date with the syntax for nwiki. I don't think they've made their way into the nwiki source. I'm not part of the nwiki team at all, I just did it for my own personal need. You might find them helpful. You can download them from:
Then just replace the existing ones in the lang directory. (back it up first just in cases!) The "how to wiki" link can be found on any edited page. See attached link.