Update manipulation.py (#40722)

python/paddle/tensor/manipulation.py

@@ -889,12 +889,20 @@ def stack(x, axis=0, name=None):
             x1 = paddle.to_tensor([[1.0, 2.0]])
             x2 = paddle.to_tensor([[3.0, 4.0]])
             x3 = paddle.to_tensor([[5.0, 6.0]])
+	    
             out = paddle.stack([x1, x2, x3], axis=0)
             print(out.shape)  # [3, 1, 2]
             print(out)
             # [[[1., 2.]],
             #  [[3., 4.]],
             #  [[5., 6.]]]
+	    
+	    out = paddle.stack([x1, x2, x3], axis=-2)
+	    print(out.shape)  # [1, 3, 2]
+	    print(out)
+	    # [[[1., 2.],
+	    #   [3., 4.],
+	    #   [5., 6.]]]
     """
     return layers.stack(x, axis, name)