message: Add missing lstm documentation caveat.
diff: @@ -376,6 +376,7 @@ See below.
  * Currently, `sequence_length` is not supported, prefer to set it to None.
  * `num_unit_shards` & `num_proj_shards` in LSTMCell are not supported as
  well.
  +* Currently, `final_state` is not supported.
  * Currently, `tf.lite.experimental.nn.dynamic_rnn` &
  `tf.lite.experimental.nn.bidirectional_dynamic_rnn` only takes
  `time_major=True`.
  