gh-132795: Add docs for multiprocessing.Semaphore.locked (GH-133299)

(cherry picked from commit de70614)

Co-authored-by: Duprat <yduprat@gmail.com>

Author: YvesDup

Doc/library/multiprocessing.rst

@@ -1419,6 +1419,12 @@ object -- see :ref:`multiprocessing-managers`.
    A solitary difference from its close analog exists: its ``acquire`` method's
    first argument is named *block*, as is consistent with :meth:`Lock.acquire`.
 
+   .. method:: locked()
+
+      Return a boolean indicating whether this object is locked right now.
+
+      .. versionadded:: 3.14
+
    .. note::
       On macOS, this is indistinguishable from :class:`Semaphore` because
       ``sem_getvalue()`` is not implemented on that platform.
@@ -1571,6 +1577,12 @@ object -- see :ref:`multiprocessing-managers`.
    A solitary difference from its close analog exists: its ``acquire`` method's
    first argument is named *block*, as is consistent with :meth:`Lock.acquire`.
 
+   .. method:: locked()
+
+      Return a boolean indicating whether this object is locked right now.
+
+      .. versionadded:: 3.14
+
 .. note::
 
    On macOS, ``sem_timedwait`` is unsupported, so calling ``acquire()`` with