subtitles m3u fix for future VLC update

YouROKrequested to merge
github/fork/PiRomant/patch-1 into master

Created by: PiRomant

sub-file dont support HTTP sourse. input-slave support .mks. With .srt and .ass problem, but they'll fix it eventually. https://code.videolan.org/videolan/vlc/-/issues/25549#note_256112

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