bpo-39245: Switch to public API for Vectorcall (GH-18460)

The bulk of this patch was generated automatically with:

    for name in \
        PyObject_Vectorcall \
        Py_TPFLAGS_HAVE_VECTORCALL \
        PyObject_VectorcallMethod \
        PyVectorcall_Function \
        PyObject_CallOneArg \
        PyObject_CallMethodNoArgs \
        PyObject_CallMethodOneArg \
    ;
    do
        echo $name
        git grep -lwz _$name | xargs -0 sed -i "s/\b_$name\b/$name/g"
    done

    old=_PyObject_FastCallDict
    new=PyObject_VectorcallDict
    git grep -lwz $old | xargs -0 sed -i "s/\b$old\b/$new/g"

and then cleaned up:

- Revert changes to in docs & news
- Revert changes to backcompat defines in headers
- Nudge misaligned comments

1 files changed, 4 insertions, 4 deletions

diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 49c26eb..aaaa447 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -454,7 +454,7 @@ classmethoddescr_call(PyMethodDescrObject *descr, PyObject *args,
     if (bound == NULL) {
         return NULL;
     }
-    PyObject *res = _PyObject_FastCallDict(bound, _PyTuple_ITEMS(args)+1,
+    PyObject *res = PyObject_VectorcallDict(bound, _PyTuple_ITEMS(args)+1,
                                            argc-1, kwds);
     Py_DECREF(bound);
     return res;
@@ -673,7 +673,7 @@ PyTypeObject PyMethodDescr_Type = {
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-    _Py_TPFLAGS_HAVE_VECTORCALL |
+    Py_TPFLAGS_HAVE_VECTORCALL |
     Py_TPFLAGS_METHOD_DESCRIPTOR,               /* tp_flags */
     0,                                          /* tp_doc */
     descr_traverse,                             /* tp_traverse */
@@ -1493,7 +1493,7 @@ property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
         return NULL;
     }
 
-    return _PyObject_CallOneArg(gs->prop_get, obj);
+    return PyObject_CallOneArg(gs->prop_get, obj);
 }
 
 static int
@@ -1514,7 +1514,7 @@ property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
         return -1;
     }
     if (value == NULL)
-        res = _PyObject_CallOneArg(func, obj);
+        res = PyObject_CallOneArg(func, obj);
     else
         res = PyObject_CallFunctionObjArgs(func, obj, value, NULL);
     if (res == NULL)