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/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 0dafb65c28..c00c2745d3 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -134,7 +134,7 @@ groupby_step(groupbyobject *gbo)
         newkey = newvalue;
         Py_INCREF(newvalue);
     } else {
-        newkey = _PyObject_CallOneArg(gbo->keyfunc, newvalue);
+        newkey = PyObject_CallOneArg(gbo->keyfunc, newvalue);
         if (newkey == NULL) {
             Py_DECREF(newvalue);
             return -1;
@@ -1219,7 +1219,7 @@ dropwhile_next(dropwhileobject *lz)
         if (lz->start == 1)
             return item;
 
-        good = _PyObject_CallOneArg(lz->func, item);
+        good = PyObject_CallOneArg(lz->func, item);
         if (good == NULL) {
             Py_DECREF(item);
             return NULL;
@@ -1382,7 +1382,7 @@ takewhile_next(takewhileobject *lz)
     if (item == NULL)
         return NULL;
 
-    good = _PyObject_CallOneArg(lz->func, item);
+    good = PyObject_CallOneArg(lz->func, item);
     if (good == NULL) {
         Py_DECREF(item);
         return NULL;
@@ -3918,7 +3918,7 @@ filterfalse_next(filterfalseobject *lz)
             ok = PyObject_IsTrue(item);
         } else {
             PyObject *good;
-            good = _PyObject_CallOneArg(lz->func, item);
+            good = PyObject_CallOneArg(lz->func, item);
             if (good == NULL) {
                 Py_DECREF(item);
                 return NULL;