feat: use loadlist when opening playlists (#929)

Opening a playlist with loadfile can lead to problems like autoload.lua
populating the playlist with other files that were in the same directory
as the playlist file.

To avoid that the command loadlist can be used to avoid having mpv treat
the file like any other, just to notice during demuxing that it is a
playlist.

src/uosc/lib/menus.lua

@@ -591,10 +591,11 @@ function open_open_file_menu()
 	menu = open_file_navigation_menu(
 		directory,
 		function(path, mods)
+			local command = has_any_extension(path, config.types.playlist) and 'loadlist' or 'loadfile'
 			if mods.ctrl then
-				mp.commandv('loadfile', path, 'append')
+				mp.commandv(command, path, 'append')
 			else
-				mp.commandv('loadfile', path)
+				mp.commandv(command, path)
 				Menu:close()
 			end
 		end,

src/uosc/main.lua

@@ -188,6 +188,7 @@ config = {
 		audio = comma_split(options.audio_types),
 		image = comma_split(options.image_types),
 		subtitle = comma_split(options.subtitle_types),
+		playlist = comma_split(options.playlist_types),
 		media = comma_split(options.video_types
 			.. ',' .. options.audio_types
 			.. ',' .. options.image_types