Fix fstrings

zz_remux/zz_remux/mux.py

@@ -87,9 +87,9 @@ class Mux:
       if merge['code'] != 0:
         err = f"Non-zero return ({merge['code']})"
       elif not temp.exists():
-        err = 'Output file missing: {temp}'
+        err = f"Output file missing: {temp}"
       elif temp.stat().st_size < (Consts.min_size * size):
-        err = 'Output file too small ({temp.stat().st_size}/{(Consts.min_size * size)})'
+        err = f"Output file too small ({temp.stat().st_size}/{(Consts.min_size * size)})"
       if err is not None:
         self.logger.error(f"Mux error ({videos[0]['group']}): {err}\n{merge['err']}\n{merge['out']}")
         continue