Fix bug when reading royalroad with extra content

see e.g. https://www.royalroad.com/fiction/36735/the-perfect-run/chapter/761960/127-theomachia

Scraper/Helper.cs

@@ -99,4 +99,12 @@ public class Helper
 		return string.Format("{0}/{1}", uri1, uri2);
 	}
 
+    public static IEnumerable<HtmlNode> RecursiveDescendants(HtmlNode n)
+    {
+	    foreach (var d1 in n.Descendants())
+	    {
+		    yield return d1;
+		    foreach (var d2 in RecursiveDescendants(d1)) yield return d2;
+	    }
+    }
 }