* Return true if we're to watch the page, false if not, null if no change.
* @param string $watchlist Valid values: 'watch', 'unwatch', 'preferences', 'nochange'
* @param Title $titleObj The page under consideration
* Return true if we're to watch the page, false if not, null if no change.
* @param string $watchlist Valid values: 'watch', 'unwatch', 'preferences', 'nochange'
* @param Title $titleObj The page under consideration