Skip reloading HTML in the detail view when the article is set and it’s the same article that was already set.

NetNewsWire/MainWindow/Detail/DetailViewController.swift

@@ -31,7 +31,9 @@ final class DetailViewController: NSViewController, WKUIDelegate {
 	
 	private var article: Article? {
 		didSet {
-			reloadHTML()
+			if article != nil, article != oldValue {
+				reloadHTML()
+			}
 		}
 	}