Fix the close-submitted hook docs in the 2.0 release notes.
Review Request #5850 — Created May 21, 2014 and submitted — Latest diff uploaded
These docs were incorrect, showing a URL that doesn't actually work.
It was missing the hosting service ID. I've updated the URL, added the
list of supported IDs, and genericified some text that was specifically
calling out GitHub/BitBucket.
Built the docs.