Youtube like/dislike video and skip ad keyboard shortcuts
Adds keyboard shortcuts [ and ] for liking and disliking videos, and s for skipping pre-video and banner ads.

Based on https://greasyfork.org/en/scripts/34049-youtube-like-dislike-video-and-skip-ad-keyboard-shortcuts/ by nerevar009 which hasn't been updated since 2017
changed skip ad button class, and added support for changing button indexed (happens when videos have dynamic buttons like "sponsor" buttons also buttons added by extensions )

This no longer works with latest youtube design.
I've switched to use https://greasyfork.org/en/scripts/437708-youtube-keyboard-shortcuts-like-dislike-backup-restore-position-change-speed-picture-in-picture instead.