Update 'right-protect', 'right-autoconfirmed' messages

* The "autoconfirmed" right is now only used to determine "newbie"
  status for the purpose of rate limiting, so I updated the
  "right-autoconfirmed" message accordingly.
* The "protect" right now does not allow the user to edit protected
  pages, so I updated the "right-protect" message accordingly.
* Also removed outdated portions of code comments referring to the
  now-fixed bug identified in r31462; the 'protect' right is now
  necessary to edit any directly or indirectly cascade-protected
  page.

Follows-up I6bf650a3fbdab8589ae6945c8c916eafd949e41c.

Change-Id: Ia3cc487dd0ad168001a076ebd612eb64764e92ef
Merge "Update 'right-protect', 'right-autoconfirmed' messages"