Mark new documents as saved (#3165)

* clean up new document message handling

* Mark new documents as saved

editor/src/messages/dialog/new_document_dialog/new_document_dialog_message_handler.rs

@@ -45,6 +45,8 @@ impl<'a> MessageHandler<NewDocumentDialogMessage, NewDocumentDialogMessageContex
 						messages: vec![DocumentMessage::ZoomCanvasToFitAll.into(), DocumentMessage::DeselectAllLayers.into()],
 					});
 				}
+
+				responses.add(DocumentMessage::MarkAsSaved);
 			}
 		}