Also a NEWS wording fixup.

the list of futures is not a list but a Future, Task or coroutine object

parameters

call_at() and run_in_executor() now raise a TypeError if the callback is a
coroutine function.

should be printed

than timeout

on Windows if source name ends with os.altsep.

on Windows if source name ends with os.altsep.

scheduled tasks should be executed or not.

test more reliable (= fail more often on Windows with HPET enabled).

_active shouldn't be cached, it set to None on shutdown.

_active shouldn't be cached, it set to None on shutdown.

Remove unused variables.

cleaning other modules.  The sys and builtins modules are cleaned last.