message: Add `available_memory_proportion` for RNNs deprecation notice in `api-changes.rst` (TF2.5)
  Summary: TF2.5 Only.
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, alfiee, markf
  Maniphest Tasks: T53099
diff: @@ -79,6 +79,18 @@ is being deprecated and will be removed in future. This feature will be provided
  methods being added via the `reduction_method` parameter
  (`tensorflow.python.ipu.optimizers.GradientAccumulationReductionMethod`).
  +RNN available_memory_proportion_fwd/available_memory_proportion_bwd deprecated
  +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  +
  +The ``available_memory_proportion_fwd`` and ``available_memory_proportion_bwd`` arguments have been deprecated and will be removed from the following layers in a future release:
  +
  + - tensorflow.python.ipu.ops.rnn_ops.PopnnLSTM
  + - tensorflow.python.ipu.ops.rnn_ops.PopnnDynamicLSTM
  + - tensorflow.python.ipu.ops.rnn_ops.PopnnGRU
  + - tensorflow.python.ipu.ops.rnn_ops.PopnnDynamicGRU
  + - tensorflow.python.ipu.ops.rnn_ops.PopnnAUGRU
  +
  +These values are now set using the ``'availableMemoryProportion'`` key of the ``options`` and ``options_bwd`` arguments correspondingly.
  Release 2.4
  ~~~~~~~~~~~
  