replace old %-formatted and .format(…) strings with f-strings (#7671)

mostly using flynt
https://github.com/ikamensh/flynt

gallery_dl/extractor/lolisafe.py

@@ -63,7 +63,7 @@ class LolisafeAlbumExtractor(LolisafeExtractor):
                     file["filename"] = file["name"] + "-" + fid
             elif "id" in file:
                 file["name"] = file["filename"]
-                file["filename"] = "{}-{}".format(file["name"], file["id"])
+                file["filename"] = f"{file['name']}-{file['id']}"
             else:
                 file["name"], sep, file["id"] = \
                     file["filename"].rpartition("-")
@@ -71,7 +71,7 @@ class LolisafeAlbumExtractor(LolisafeExtractor):
             yield Message.Url, url, file
 
     def fetch_album(self, album_id):
-        url = "{}/api/album/get/{}".format(self.root, album_id)
+        url = f"{self.root}/api/album/get/{album_id}"
         data = self.request(url).json()
 
         return data["files"], {