bpo-36542: Allow to overwrite the signature for Python functions. (GH-12705)

diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py
index 0a61e3a..2af31a1 100644
--- a/Lib/concurrent/futures/thread.py
+++ b/Lib/concurrent/futures/thread.py
@@ -174,6 +174,7 @@
             self._work_queue.put(w)
             self._adjust_thread_count()
             return f
+    submit.__text_signature__ = _base.Executor.submit.__text_signature__
     submit.__doc__ = _base.Executor.submit.__doc__
 
     def _adjust_thread_count(self):