bpo-39744: update docs

Author: marmarek

Doc/library/asyncio-subprocess.rst

@@ -230,6 +230,10 @@ their completion.
       Note, that the data read is buffered in memory, so do not use
       this method if the data size is large or unlimited.
 
+      .. versionchanged:: 3.12
+
+         *stdin* gets closed when `input=None` too.
+
    .. method:: send_signal(signal)
 
       Sends the signal *signal* to the child process.

Misc/NEWS.d/next/Library/2020-02-25-00-43-22.bpo-39744.hgK689.rst

@@ -1 +1 @@
-Make func:``asyncio.subprocess.Process.communicate`` close subprocess's stdin even when called with input=None
+Make func:``asyncio.subprocess.Process.communicate`` close subprocess's stdin even when called with `input=None`