gh-56133: copyreg docs: Clarify function/constructor parameter (GH-95497)

(cherry picked from commit 281a3f18cc2afac0fa92c75e807775971e531711)

Co-authored-by: Stanley <46876382+slateny@users.noreply.github.com>

diff --git a/Doc/library/copyreg.rst b/Doc/library/copyreg.rst
index dc35965be3e40db19dbdd53824125c6fe31f4a6e..866b180f4bc3b829bc13e59d04a05e537badadd8 100644 (file)
--- a/Doc/library/copyreg.rst
+++ b/Doc/library/copyreg.rst
@@ -25,20 +25,17 @@ Such constructors may be factory functions or class instances.
    hence not valid as a constructor), raises :exc:`TypeError`.
 
 
-.. function:: pickle(type, function, constructor=None)
+.. function:: pickle(type, function, constructor_ob=None)
 
    Declares that *function* should be used as a "reduction" function for objects
    of type *type*.  *function* should return either a string or a tuple
-   containing two or three elements.
+   containing two or three elements. See the :attr:`~pickle.Pickler.dispatch_table`
+   for more details on the interface of *function*.
 
-   The optional *constructor* parameter, if provided, is a callable object which
-   can be used to reconstruct the object when called with the tuple of arguments
-   returned by *function* at pickling time.  A :exc:`TypeError` is raised if the
-   *constructor* is not callable.
+   The *constructor_ob* parameter is a legacy feature and is now ignored, but if
+   passed it must be a callable.
 
-   See the :mod:`pickle` module for more details on the interface
-   expected of *function* and *constructor*.  Note that the
-   :attr:`~pickle.Pickler.dispatch_table` attribute of a pickler
+   Note that the :attr:`~pickle.Pickler.dispatch_table` attribute of a pickler
    object or subclass of :class:`pickle.Pickler` can also be used for
    declaring reduction functions.