PLWI: Fix _fps_reset pathlib usage, stem and suffix was mixed up

Author: rlaphoenix

pvsfunc/plwi.py

@@ -103,7 +103,7 @@ def _fps_reset(file_path: Path) -> Path:
  if video_track.original_frame_rate is None:
  # no container-set FPS to remove, return unchanged
  return file_path
- out_path = file_path.with_stem(".pfpsreset.mkv")
+ out_path = file_path.with_suffix(".pfpsreset.mkv")
  if out_path.is_file():
  # an fps reset was already run on this file, re-use
  # TODO: could be untrusted, user might just make a file named this