Use Python 3.13a4 PyCFunctionFastWithKeywords

Python 3.13a4 adds a public PyCFunctionFastWithKeywords type.

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

Python 3.13a1 removed the private _PyCFunctionFastWithKeywords type.

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

@@ -908,7 +908,11 @@ class __Pyx_FakeReference {
                                                           Py_ssize_t nargs, PyObject *kwnames);
 #else
   #define __Pyx_PyCFunctionFast _PyCFunctionFast
-  #define __Pyx_PyCFunctionFastWithKeywords _PyCFunctionFastWithKeywords
+  #if PY_VERSION_HEX >= 0x030D00A4
+  #  define __Pyx_PyCFunctionFastWithKeywords PyCFunctionFastWithKeywords
+  #else
+  #  define __Pyx_PyCFunctionFastWithKeywords _PyCFunctionFastWithKeywords
+  #endif
 #endif
 
 #if CYTHON_METH_FASTCALL