message: [tf.data] Document `tf.data.Dataset.from_generator()` anti-pattern.
diff: @@ -818,6 +818,12 @@ class DatasetV2(collections_abc.Iterable, tracking_base.Trackable,
  cache any external state in `generator` before calling
  `Dataset.from_generator()`.
  + Note: While the `output_signature` parameter makes it possible to yield
  + `Dataset` elements, the scope of `Dataset.from_generator()` should be
  + limited to logic that cannot be expressed through tf.data operations. Using
  + tf.data operations within the generator function is an anti-pattern and may
  + result in incremental memory growth.
  +
  Args:
  generator: A callable object that returns an object that supports the
  `iter()` protocol. If `args` is not specified, `generator` must take no
  