fixed issue when trying to save again the same page

Former-commit-id: a4026aa320c981103eb1d2c795f5abc8027eda6c

extension/core/bg/downloads.js

@@ -87,6 +87,7 @@ singlefile.extension.core.bg.downloads = (() => {
 			if (options.autoClose) {
 				singlefile.extension.core.bg.tabs.remove(sender.tab.id);
 			}
+			return {};
 		}
 	}