message: Update docstring of tf.linespace for 0-D inputs
  In 20258 the question was raised as tf.linespace
  only supports 0-D inputs of start/stop, but the docstring
  did not mention the 0-D restriction.
  This fix updates the docstring to address the discrepancy.
  This fix fixes 20258.
diff: @@ -3,13 +3,13 @@ op {
  in_arg {
  name: "start"
  description: <<END
  -First entry in the range.
  +0-D tensor. First entry in the range.
  END
  }
  in_arg {
  name: "stop"
  description: <<END
  -Last entry in the range.
  +0-D tensor. Last entry in the range.
  END
  }
  in_arg {
  