&$fields: array of query fields
$values: array of variables with watchlist options
+'SpecialWatchlistGetNonRevisionTypes': Called when building sql query for
+SpecialWatchlist. Allows extensions to register custom values they have
+inserted to rc_type so they can be returned as part of the watchlist.
+&$nonRevisionTypes: array of values in the rc_type field of recentchanges table
+
'TestCanonicalRedirect': Called when about to force a redirect to a canonical
URL for a title when we have no other parameters on the URL. Gives a chance for
extensions that alter page view behavior radically to abort that redirect or
'UserClearNewTalkNotification': Called when clearing the "You have new
messages!" message, return false to not delete it.
$user: User (object) that will clear the message
+$oldid: ID of the talk page revision being viewed (0 means the most recent one)
'UserComparePasswords': Called when checking passwords, return false to
override the default password checks.