#16978: merge with 3.2.

diff --cc Doc/library/threading.rst
index 05863a0e731400af46ee794487619574e78a7ee4,4a0121168711aca15951712a7691468744d9ff88..ec235046ce781024fb5ffc06b2779345bb2c1099
--- 1/Doc/library/threading.rst
--- 2/Doc/library/threading.rst
+++ b/Doc/library/threading.rst
@@@ -306,18 -368,6 +306,18 @@@ since it is impossible to detect the te
        property instead.
  
  
-    Due to the :term:`Global Interpreter Lock`, in CPython only one thread
 +.. impl-detail::
 +
-    If you want your application to make better of use of the computational
++   In CPython, due to the :term:`Global Interpreter Lock`, only one thread
 +   can execute Python code at once (even though certain performance-oriented
 +   libraries might overcome this limitation).
++   If you want your application to make better use of the computational
 +   resources of multi-core machines, you are advised to use
 +   :mod:`multiprocessing` or :class:`concurrent.futures.ProcessPoolExecutor`.
 +   However, threading is still an appropriate model if you want to run
 +   multiple I/O-bound tasks simultaneously.
 +
 +
  .. _lock-objects:
  
  Lock Objects