bpo-34369: make kqueue.control() docs better reflect that timeout is positional-only (GH-9499)

(cherry picked from commit 79042ac4348ccc09344014f20dd49401579f8795)

Co-authored-by: Tal Einat <taleinat@gmail.com>
diff --git a/Doc/library/select.rst b/Doc/library/select.rst
index 733a91e..8f5a2ce 100644
--- a/Doc/library/select.rst
+++ b/Doc/library/select.rst
@@ -480,13 +480,14 @@
    Create a kqueue object from a given file descriptor.
 
 
-.. method:: kqueue.control(changelist, max_events[, timeout=None]) -> eventlist
+.. method:: kqueue.control(changelist, max_events[, timeout]) -> eventlist
 
    Low level interface to kevent
 
-   - changelist must be an iterable of kevent object or ``None``
+   - changelist must be an iterable of kevent objects or ``None``
    - max_events must be 0 or a positive integer
-   - timeout in seconds (floats possible)
+   - timeout in seconds (floats possible); the default is ``None``,
+     to wait forever
 
    .. versionchanged:: 3.5
       The function is now retried with a recomputed timeout when interrupted by