Revert "adding *ctxkwargs* to ThreadPoolExecutor"

Author: donbarbos

Doc/library/concurrent.futures.rst

@@ -147,7 +147,7 @@ And::
    executor.submit(wait_on_future)
 
 
-.. class:: ThreadPoolExecutor(max_workers=None, thread_name_prefix='', initializer=None, initargs=(), **ctxkwargs)
+.. class:: ThreadPoolExecutor(max_workers=None, thread_name_prefix='', initializer=None, initargs=())
 
    An :class:`Executor` subclass that uses a pool of at most *max_workers*
    threads to execute calls asynchronously.
@@ -194,10 +194,6 @@ And::
       Default value of *max_workers* is changed to
       ``min(32, (os.process_cpu_count() or 1) + 4)``.
 
-   .. versionchanged:: next
-      Added *ctxkwargs* to pass additional arguments to ``cls.prepare_context``
-      class method.
-
 
 .. _threadpoolexecutor-example: