docs(mge): update AvgPool2d example

GitOrigin-RevId: 2d5e51505587386a4318371747a8a470aa885fda

imperative/python/megengine/module/pooling.py

@@ -94,6 +94,7 @@ class AvgPool2d(_PoolNd):
         >>> m = M.AvgPool2d(kernel_size=2, stride=2, padding=[1,0], mode="average")
         >>> inp = mge.tensor(np.arange(1 * 1 * 3 * 4).astype(np.float32).reshape(1, 1, 3, 4))
         >>> output = m(inp)
+        >>> output
         Tensor([[[[0.25 1.25]
                   [6.5  8.5 ]]]], device=xpux:0)