Detail pages, link previews, RSS, and sitemap fixed

Some article, incident, event, vacancy, business, course, and classified pages were showing a 'Not Found' message even when the item existed. Social link previews on those pages were also falling back to a generic image, and our RSS feed and sitemap had been returning empty. All of these now load correctly. If you ran into a 'Not Found' page on a link you knew was valid, give it another try — it should work now.