[twitter] remove 'syndication' option (#3889)

docs/configuration.rst

@@ -3262,8 +3262,6 @@ Description
     for each Tweet in said timeline.
 
     Note: This requires at least 1 additional API call per initial Tweet.
-    Age-restricted replies cannot be expanded when using the
-    `syndication <extractor.twitter.syndication_>`__ API.
 
 
 extractor.twitter.include
@@ -3331,30 +3329,6 @@ Description
     ``4096x4096``, ``orig``, ``large``, ``medium``, and ``small``.
 
 
-extractor.twitter.syndication
------------------------------
-Type
-    * ``bool``
-    * ``string``
-Default
-    ``false``
-Description
-    Controls how to retrieve age-restricted content when not logged in.
-
-    * ``false``: Skip age-restricted Tweets.
-    * ``true``: Download using Twitter's syndication API.
-    * ``"extended"``: Try to fetch Tweet metadata using the normal API
-      in addition to the syndication API. This requires additional HTTP
-      requests in some cases (e.g. when `retweets <extractor.twitter.retweets_>`_
-      are enabled).
-
-    Note: This does not apply to search results (including
-    `timeline strategies <extractor.twitter.timeline.strategy_>`__).
-    To retrieve such content from search results, you must log in and
-    disable "Hide sensitive content" in your `search settings
-    <https://twitter.com/settings/search>`__.
-
-
 extractor.twitter.logout
 ------------------------
 Type