message: Improve readability of several sparse_ops docstrings.
diff: @@ -491,6 +491,7 @@ def sparse_cross(inputs, name=None):
  """Generates sparse cross from a list of sparse and dense tensors.
  For example, if the inputs are
  +
  * inputs[0]: SparseTensor with shape = [2, 2]
  [0, 0]: "a"
  [1, 0]: "b"
  @@ -501,6 +502,7 @@ def sparse_cross(inputs, name=None):
  * inputs[2]: Tensor [["f"], ["g"]]
  then the output will be:
  +
  shape = [2, 2]
  [0, 0]: "a_X_d_X_f"
  [1, 0]: "b_X_e_X_g"
  @@ -524,6 +526,7 @@ def sparse_cross_hashed(inputs, num_buckets=0, hash_key=None, name=None):
  """Generates hashed sparse cross from a list of sparse and dense tensors.
  For example, if the inputs are
  +
  * inputs[0]: SparseTensor with shape = [2, 2]
  [0, 0]: "a"
  [1, 0]: "b"
  @@ -534,6 +537,7 @@ def sparse_cross_hashed(inputs, num_buckets=0, hash_key=None, name=None):
  * inputs[2]: Tensor [["f"], ["g"]]
  then the output will be:
  +
  shape = [2, 2]
  [0, 0]: FingerprintCat64(
  Fingerprint64("f"), FingerprintCat64(
  