prioritize xmltv_ns over onscreen for episode-num

ErsatzTV.Core/Iptv/ChannelGuide.cs

@@ -105,13 +105,13 @@ namespace ErsatzTV.Core.Iptv
                         if (s > 0 && e > 0)
                         {
                             xml.WriteStartElement("episode-num");
-                            xml.WriteAttributeString("system", "xmltv_ns");
+                            xml.WriteAttributeString("system", "onscreen");
-                            xml.WriteString($"{s - 1}.{e - 1}.0/1");
+                            xml.WriteString($"S{s:00}E{e:00}");
                             xml.WriteEndElement(); // episode-num
                             
                             xml.WriteStartElement("episode-num");
-                            xml.WriteAttributeString("system", "onscreen");
+                            xml.WriteAttributeString("system", "xmltv_ns");
-                            xml.WriteString($"S{s:00}E{e:00}");
+                            xml.WriteString($"{s - 1}.{e - 1}.0/1");
                             xml.WriteEndElement(); // episode-num
                         }
                     }