gh-76075: Correct datetime.timestamp documentation

Doc/library/datetime.rst

@@ -1485,10 +1485,10 @@
    instance. The return value is a :class:`float` similar to that
    returned by :func:`time.time`.
 
    Naive :class:`.datetime` instances are assumed to represent local
-   time and this method relies on the platform C :c:func:`mktime`
+   time and this method relies on the platform C :c:func:`locatime_s`
    function to perform the conversion. Since :class:`.datetime`
-   supports wider range of values than :c:func:`mktime` on many
+   supports wider range of values than :c:func:`locatime_s` on many
    platforms, this method may raise :exc:`OverflowError` or :exc:`OSError`
    for times far in the past or far in the future.
 
@@ -1503,6 +1503,10 @@
       The :meth:`timestamp` method uses the :attr:`.fold` attribute to
       disambiguate the times during a repeated interval.
 
+   .. versionchanged:: 3.6
+      This method no longer relies on the platform C :c:func:`mktime`
+      function to perform conversions.
+
    .. note::
 
       There is no method to obtain the POSIX timestamp directly from a