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, 1 insertions, 1 deletions

diff --git a/Objects/classobject.c b/Objects/classobject.c
index fb89b8aa69..33afbcd874 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -350,7 +350,7 @@ PyTypeObject PyMethod_Type = {
     PyObject_GenericSetAttr,                    /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-    _Py_TPFLAGS_HAVE_VECTORCALL,                /* tp_flags */
+    Py_TPFLAGS_HAVE_VECTORCALL,                 /* tp_flags */
     method_doc,                                 /* tp_doc */
     (traverseproc)method_traverse,              /* tp_traverse */
     0,                                          /* tp_clear */