[documentaion] Document `playable_in_embed`

:ci skip all

README.md

@@ -802,6 +802,7 @@ The available fields are:
  - `age_limit` (numeric): Age restriction for the video (years)
  - `is_live` (boolean): Whether this video is a live stream or a fixed-length video
  - `was_live` (boolean): Whether this video was originally a live stream
+ - `playable_in_embed` (string): Whether this video is allowed to play in embedded players on other sites
  - `start_time` (numeric): Time in seconds where the reproduction should start, as specified in the URL
  - `end_time` (numeric): Time in seconds where the reproduction should end, as specified in the URL
  - `format` (string): A human-readable description of the format

youtube_dlc/extractor/common.py

@@ -290,6 +290,10 @@ class InfoExtractor(object):
                         * "start_time" - The start time of the chapter in seconds
                         * "end_time" - The end time of the chapter in seconds
                         * "title" (optional, string)
+    playable_in_embed: Whether this video is allowed to play in embedded
+                    players on other sites. Can be True (=always allowed),
+                    False (=never allowed), None (=unknown), or a string
+                    specifying the criteria for embedability (Eg: 'whitelist').
 
     The following fields should only be used when the video belongs to some logical
     chapter or section: