fix doc warning (#4959)

docs/langref/relay_op.rst

@@ -196,15 +196,15 @@ This level support backpropagation of broadcast operators. It is temporary.
    tvm.relay.collapse_sum_like
    tvm.relay.slice_like
    tvm.relay.shape_of
-   tvm.relay.contrib.ndarray_size
+   tvm.relay.ndarray_size
    tvm.relay.layout_transform
    tvm.relay.device_copy
    tvm.relay.annotation.on_device
    tvm.relay.reverse_reshape
    tvm.relay.sequence_mask
    tvm.relay.nn.batch_matmul
-   tvm.relay.contrib.adaptive_max_pool2d
-   tvm.relay.contrib.adaptive_avg_pool2d
+   tvm.relay.nn.adaptive_max_pool2d
+   tvm.relay.nn.adaptive_avg_pool2d
    tvm.relay.one_hot
 
 
@@ -355,15 +355,15 @@ Level 10 Definitions
 .. autofunction:: tvm.relay.collapse_sum_like
 .. autofunction:: tvm.relay.slice_like
 .. autofunction:: tvm.relay.shape_of
-.. autofunction:: tvm.relay.contrib.ndarray_size
+.. autofunction:: tvm.relay.ndarray_size
 .. autofunction:: tvm.relay.layout_transform
 .. autofunction:: tvm.relay.device_copy
 .. autofunction:: tvm.relay.annotation.on_device
 .. autofunction:: tvm.relay.reverse_reshape
 .. autofunction:: tvm.relay.sequence_mask
 .. autofunction:: tvm.relay.nn.batch_matmul
-.. autofunction:: tvm.relay.contrib.adaptive_max_pool2d
-.. autofunction:: tvm.relay.contrib.adaptive_avg_pool2d
+.. autofunction:: tvm.relay.nn.adaptive_max_pool2d
+.. autofunction:: tvm.relay.nn.adaptive_avg_pool2d
 .. autofunction:: tvm.relay.one_hot