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

GitOrigin-RevId: c2ac7bab326019132640974472067b9454d5d200

imperative/python/megengine/functional/nn.py

@@ -45,7 +45,6 @@ __all__ = [
     "max_pool2d",
     "one_hot",
     "prelu",
-    "roi_align",
     "roi_pooling",
     "softmax",
     "softplus",
@@ -1382,7 +1381,7 @@ def roi_align(
             np.random.seed(42)
             inp = tensor(np.random.randn(1, 1, 128, 128))
             rois = tensor(np.random.random((4, 5)))
-            y = F.roi_align(inp, rois, (2, 2))
+            y = F.nn.roi_align(inp, rois, (2, 2))
             print(y.numpy()[0])
 
     Outputs:

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

@@ -170,7 +170,7 @@ def test_roi_align():
     grad = Grad().wrt(inp_feat, callback=_save_to(inp_feat))
 
     output_shape = (7, 7)
-    out_feat = F.roi_align(
+    out_feat = F.nn.roi_align(
         inp_feat,
         rois,
         output_shape=output_shape,