Using https://github.com/asottile/pyupgrade
1. `__future__` imports and `coding: utf-8` were removed
2. Files were rewritten with `pyupgrade --py36-plus --keep-percent-format`
3. f-strings were cherry-picked from `pyupgrade --py36-plus`
Extractors are left untouched (except removing header) to avoid unnecessary merge conflicts
_parse_ism_formats was extended into _parse_ism_formats_and_subtitles;
all direct users were updated, though _extract_ism_formats was left
as a compatibility wrapper.
The SSTR downloader was also modified in order to prepare for muxing
subtitle streams, although no support for any subtitle codecs was
added in this commit.
* All modules and binary names are changed
* All documentation references changed
* yt-dlp no longer loads youtube-dlc config files
* All URLs changed to point to organization account
Co-authored-by: Pccode66
Co-authored-by: pukkandan
