Fix _PyList_Extend for Python 3.13

[cdce8p]

Replace _PyList_Extend with PyList_Extend from pythoncapi_compat.h.

python/cpython#111138
https://docs.python.org/dev/c-api/list.html#c.PyList_Extend

Fixes

  /home/runner/work/mypy/mypy/mypyc/lib-rt/list_ops.c: In function ‘CPyList_Extend’: (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/list_ops.c:259:12: error: implicit declaration of function ‘_PyList_Extend’; did you mean ‘CPyList_Extend’? [-Werror=implicit-function-declaration] (diff)
    259 |     return _PyList_Extend((PyListObject *)o1, o2); (diff)
        |            ^~~~~~~~~~~~~~ (diff)
        |            CPyList_Extend (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/list_ops.c:259:12: error: returning ‘int’ from a function with return type ‘PyObject *’ {aka ‘struct _object *’} makes pointer from integer without a cast [-Werror=int-conversion] (diff)
    259 |     return _PyList_Extend((PyListObject *)o1, o2); (diff)
        |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/dict_ops.c: In function ‘CPyDict_Keys’: (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/dict_ops.c:233:21: error: initialization of ‘PyObject *’ {aka ‘struct _object *’} from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion] (diff)
    233 |     PyObject *res = _PyList_Extend((PyListObject *)list, view); (diff)
        |                     ^~~~~~~~~~~~~~ (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/dict_ops.c: In function ‘CPyDict_Values’: (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/dict_ops.c:253:21: error: initialization of ‘PyObject *’ {aka ‘struct _object *’} from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion] (diff)
    253 |     PyObject *res = _PyList_Extend((PyListObject *)list, view); (diff)
        |                     ^~~~~~~~~~~~~~ (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/dict_ops.c: In function ‘CPyDict_Items’: (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/dict_ops.c:273:21: error: initialization of ‘PyObject *’ {aka ‘struct _object *’} from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion] (diff)
    273 |     PyObject *res = _PyList_Extend((PyListObject *)list, view); (diff)
        |                     ^~~~~~~~~~~~~~ (diff)