!5094 Fix sliceOp API

Merge pull request !5094 from h.farahat/master

mindspore/dataset/transforms/c_transforms.py

@@ -85,6 +85,7 @@ class Slice(cde.SliceOp):
         slices(Union[int, list(int), slice, None, Ellipses]):
             Maximum `n` number of arguments to slice a tensor of rank `n`.
             One object in slices can be one of:
+
             1.  :py:obj:`int`: Slice this index only. Negative index is supported.
             2.  :py:obj:`list(int)`: Slice these indices ion the list only. Negative indices are supported.
             3.  :py:obj:`slice`: Slice the generated indices from the slice object. Similar to `start:stop:step`.