fix unstack op doc (#26268)

python/paddle/fluid/layers/nn.py

@@ -11139,12 +11139,12 @@ def unstack(x, axis=0, num=None):
     raised.
 
     Args:
-        x (Variable): Input Tensor. It is a N-D Tensors of data types float32, float64, int32, int64.
+        x (Tensor): Input Tensor. It is a N-D Tensors of data types float32, float64, int32, int64.
         axis (int): The axis along which the input is unstacked.
         num (int|None): The number of output variables.
 
     Returns:
-        list(Variable): The unstacked Tensors list. The list elements are N-D Tensors of data types float32, float64, int32, int64.
+        list(Tensor): The unstacked Tensors list. The list elements are N-D Tensors of data types float32, float64, int32, int64.
 
     Raises:
         ValueError: If x.shape[axis] <= 0 or axis is not in range [-D, D).
@@ -11153,7 +11153,7 @@ def unstack(x, axis=0, num=None):
         .. code-block:: python
 
             import paddle.fluid as fluid
-            x = fluid.layers.data(name='x', shape=[2, 3, 5], dtype='float32')  # create a tensor with shape=[2, 3, 5]
+            x = fluid.data(name='x', shape=[2, 3, 5], dtype='float32')  # create a tensor with shape=[2, 3, 5]
             y = fluid.layers.unstack(x, axis=1)  # unstack with second axis, which results 3 tensors with shape=[2, 5]
 
     """