feat(mge): do not export F.nn.roi_pooling

GitOrigin-RevId: 8a07dd1da4af3a1322455cf4fcb49a9a4bbe018e

imperative/python/megengine/functional/nn.py

@@ -45,7 +45,6 @@ __all__ = [
     "max_pool2d",
     "one_hot",
     "prelu",
-    "roi_pooling",
     "softmax",
     "softplus",
     "svd",
@@ -1324,7 +1323,7 @@ def roi_pooling(
             np.random.seed(42)
             inp = tensor(np.random.randn(1, 1, 128, 128))
             rois = tensor(np.random.random((4, 5)))
-            y = F.roi_pooling(inp, rois, (2, 2))
+            y = F.nn.roi_pooling(inp, rois, (2, 2))
             print(y.numpy()[0])
 
     Outputs:

imperative/python/test/unit/functional/test_functional.py

@@ -193,7 +193,7 @@ def test_roi_pooling():
     inp_feat, rois = _gen_roi_inp()
     grad = Grad().wrt(inp_feat, callback=_save_to(inp_feat))
     output_shape = (7, 7)
-    out_feat = F.roi_pooling(
+    out_feat = F.nn.roi_pooling(
         inp_feat, rois, output_shape=output_shape, mode="max", scale=1.0 / 4,
     )
     assert make_shape_tuple(out_feat.shape) == (