replace more '.format(…)' calls with f-strings (#7671)

gallery_dl/extractor/mangadex.py

@@ -354,7 +354,7 @@ class MangadexAPI():
                 self.extractor.wait(until=until)
                 continue
 
-            msg = ", ".join('{title}: "{detail}"'.format_map(error)
+            msg = ", ".join(f'{error["title"]}: "{error["detail"]}"'
                             for error in response.json()["errors"])
             raise exception.AbortExtraction(
                 f"{response.status_code} {response.reason} ({msg})")