!21640 Updated the description of operators batch_dot and sequence_mask

Merge pull request !21640 from dinglinhe/code_docs_dlh_ms_I44KL5

mindspore/ops/composite/array_ops.py

@@ -139,7 +139,7 @@ def sequence_mask(lengths, maxlen=None):
           less than or equal to `maxlen`. Values greater than `maxlen` will be treated as `maxlen`.
           Must be type int32 or int64.
         - **maxlen** (int) - size of the last dimension of returned tensor. Must be positive and same
-          type as elements in `lengths`.
+          type as elements in `lengths`. Default is None.
 
     Outputs:
         One mask tensor of shape lengths.shape + (maxlen,).

mindspore/ops/composite/math_ops.py

@@ -528,6 +528,7 @@ def batch_dot(x1, x2, axes=None):
         - **axes** (Union[int, tuple(int), list(int)]) - Single value or tuple/list of length 2 with dimensions
           specified for `a` and `b` each. If single value `N` passed, automatically picks up last N dims from
           `a` input shape and last N dimensions from `b` input shape in order as axes for each respectively.
+          Default: None.
 
     Outputs:
         Tensor, batch dot product of `x1` and `x2`.For example: The Shape of output