Use Python 3.13a4 PyCFunctionFastWithKeywords

Python 3.13a4 adds a public PyCFunctionFastWithKeywords and
PyCFunctionFast types and removes the private
_PyCFunctionFastWithKeywords and _PyCFunctionFast types:

* python/cpython@9e3729b
* python/cpython#114627
* capi-workgroup/decisions#11

Cython/Utility/CythonFunction.c

@@ -1019,7 +1019,7 @@ static PyObject * __Pyx_CyFunction_Vectorcall_FASTCALL_KEYWORDS(PyObject *func,
         return NULL;
     }
 
-    return ((_PyCFunctionFastWithKeywords)(void(*)(void))def->ml_meth)(self, args, nargs, kwnames);
+    return ((__Pyx_PyCFunctionFastWithKeywords)(void(*)(void))def->ml_meth)(self, args, nargs, kwnames);
 }
 
 static PyObject * __Pyx_CyFunction_Vectorcall_FASTCALL_KEYWORDS_METHOD(PyObject *func, PyObject *const *args, size_t nargsf, PyObject *kwnames)

Cython/Utility/ModuleSetupCode.c

@@ -907,8 +907,13 @@ class __Pyx_FakeReference {
   typedef PyObject *(*__Pyx_PyCFunctionFastWithKeywords) (PyObject *self, PyObject *const *args,
                                                           Py_ssize_t nargs, PyObject *kwnames);
 #else
-  #define __Pyx_PyCFunctionFast _PyCFunctionFast
-  #define __Pyx_PyCFunctionFastWithKeywords _PyCFunctionFastWithKeywords
+  #if PY_VERSION_HEX >= 0x030d00A4
+  #  define __Pyx_PyCFunctionFast PyCFunctionFast
+  #  define __Pyx_PyCFunctionFastWithKeywords PyCFunctionFastWithKeywords
+  #else
+  #  define __Pyx_PyCFunctionFast _PyCFunctionFast
+  #  define __Pyx_PyCFunctionFastWithKeywords _PyCFunctionFastWithKeywords
+  #endif
 #endif
 
 #if CYTHON_METH_FASTCALL