bpo-47220: Document the optional callback parameter of weakref.WeakMethod (GH-25491)

(cherry picked from commit 9628136)

Co-authored-by: Géry Ogam <[email protected]>

Author: miss-islington

Doc/library/weakref.rst

@@ -143,7 +143,7 @@ See :ref:`__slots__ documentation <slots>` for details.
    ``ProxyType`` or ``CallableProxyType``, depending on whether *object* is
    callable.  Proxy objects are not :term:`hashable` regardless of the referent; this
    avoids a number of problems related to their fundamentally mutable nature, and
-   prevent their use as dictionary keys.  *callback* is the same as the parameter
+   prevents their use as dictionary keys.  *callback* is the same as the parameter
    of the same name to the :func:`ref` function.
 
    Accessing an attribute of the proxy object after the referent is
@@ -212,7 +212,7 @@ objects.
    discarded when no strong reference to it exists any more.
 
 
-.. class:: WeakMethod(method)
+.. class:: WeakMethod(method[, callback])
 
    A custom :class:`ref` subclass which simulates a weak reference to a bound
    method (i.e., a method defined on a class and looked up on an instance).
@@ -238,6 +238,8 @@ objects.
       >>> r()
       >>>
 
+   *callback* is the same as the parameter of the same name to the :func:`ref` function.
+
    .. versionadded:: 3.4
 
 .. class:: finalize(obj, func, /, *args, **kwargs)

Misc/NEWS.d/next/Library/2022-04-04-22-54-11.bpo-47220.L9jYu4.rst

@@ -0,0 +1,2 @@
+Document the optional *callback* parameter of :class:`WeakMethod`. Patch by
+Géry Ogam.