In the contributors documentation, I inserted a note saying how to add an extra remote that links to the main master repository and not your own, should you wish to pull from there instead of your github repository.

I didn't find it entirely obvious the first time I set it all up on my system why one would want to make remotes to other things, so I thought it'd be good to add this note within the context of the documentation.

I feel it's in a good location too, seeing as the line

(If any of the above seems like magic to you, then look up the
Git documentation <http://git-scm.com/documentation>_ on the web.)

follows it directly.

Please let me know if you think I can word it better or if you find this unnecessary.
J