gh-80334: Doc/library/multiprocessing.rst: freeze_support: Change to specify spawn method instead of platform

Author: eddymul

Doc/library/multiprocessing.rst

@@ -1081,7 +1081,7 @@ Miscellaneous
 .. function:: freeze_support()
 
    Add support for when a program which uses :mod:`multiprocessing` has been
-   frozen to produce a Windows executable.  (Has been tested with **py2exe**,
+   frozen to produce an executable.  (Has been tested with **py2exe**,
    **PyInstaller** and **cx_Freeze**.)
 
    One needs to call this function straight after the ``if __name__ ==
@@ -1099,9 +1099,8 @@ Miscellaneous
    If the ``freeze_support()`` line is omitted then trying to run the frozen
    executable will raise :exc:`RuntimeError`.
 
-   Calling ``freeze_support()`` has no effect when invoked on any operating
-   system other than Windows.  In addition, if the module is being run
-   normally by the Python interpreter on Windows (the program has not been
+   Calling ``freeze_support()`` has no effect when the start method is not *spawn*. In addition, if the module is being run
+   normally by the Python interpreter (the program has not been
    frozen), then ``freeze_support()`` has no effect.
 
 .. function:: get_all_start_methods()