[options] Fix a typo (#6307)

youtube_dl/options.py

@@ -219,7 +219,7 @@ def parseOpts(overrideArguments=None):
     selection.add_option(
         '--playlist-items',
         dest='playlist_items', metavar='ITEM_SPEC', default=None,
-        help='Playlist video items to download. Specify indices of the videos in the playlist seperated by commas like: "--playlist-items 1,2,5,8" if you want to download videos indexed 1, 2, 5, 8 in the playlist. You can specify range: "--playlist-items 1-3,7,10-13", it will download the videos at index 1, 2, 3, 7, 10, 11, 12 and 13.')
+        help='Playlist video items to download. Specify indices of the videos in the playlist separated by commas like: "--playlist-items 1,2,5,8" if you want to download videos indexed 1, 2, 5, 8 in the playlist. You can specify range: "--playlist-items 1-3,7,10-13", it will download the videos at index 1, 2, 3, 7, 10, 11, 12 and 13.')
     selection.add_option(
         '--match-title',
         dest='matchtitle', metavar='REGEX',