refactor: fixed xo aspect

Unnecessary return statement. (no-useless-return)XO(no-useless-return)

Author: mfranzke

loading-attribute-polyfill.sw.js

@@ -28,7 +28,5 @@ self.addEventListener('fetch', (event) => {
 				)
 			);
 		}
-
-		return;
 	}
 });