message: [tf.data] Update the documentation for `enable_debug_mode`.
diff: @@ -5120,12 +5120,24 @@ DEBUG_MODE = False
  def enable_debug_mode():
  """Enables debug mode for tf.data.
  - Example usage:
  + Example usage with pdb module:
  ```
  import tensorflow as tf
  + import pdb
  tf.data.experimental.enable_debug_mode()
  - ds = ... # input pipeline definition
  +
  + def func(x):
  + # Python 3.7 and older requires `pdb.Pdb(nosigint=True).set_trace()`
  + pdb.set_trace()
  + x = x + 1
  + return x
  +
  + dataset = tf.data.Dataset.from_tensor_slices([1, 2, 3])
  + dataset = dataset.map(func)
  +
  + for item in dataset:
  + print(item)
  ```
  The effect of debug mode is two-fold:
  