Fix the C function signature for _collections._tuplegetter.__reduce__. (GH-12180)

Correctly fixes bpo-36197.

Modules/_collectionsmodule.c

@@ -2441,7 +2441,7 @@ tuplegetter_dealloc(_tuplegetterobject *self)
 }
 
 static PyObject*
-tuplegetter_reduce(_tuplegetterobject *self)
+tuplegetter_reduce(_tuplegetterobject *self, PyObject *Py_UNUSED(ignored))
 {
     return Py_BuildValue("(O(nO))", (PyObject*) Py_TYPE(self), self->index, self->doc);
 }
@@ -2453,7 +2453,7 @@ static PyMemberDef tuplegetter_members[] = {
 };
 
 static PyMethodDef tuplegetter_methods[] = {
-    {"__reduce__", (PyCFunction)(void(*)(void))tuplegetter_reduce, METH_NOARGS, NULL},
+    {"__reduce__", (PyCFunction)tuplegetter_reduce, METH_NOARGS, NULL},
     {NULL},
 };