message: TensorFlow doc: fix some RST syntax errors
  Test Plan: built locally
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, georgep
  Subscribers: georgep
  Maniphest Tasks: T49194
diff: @@ -29,6 +29,7 @@ functions.
  Usage
  ~~~~~
  +
  The IPU embedded application runtime relies on instances of the
  ``RuntimeContext`` class to coordinate the startup and calls to the Poplar
  engine. This object is created with a call to
  @@ -50,6 +51,7 @@ function can be called. The context object ensures all appropriate metadata is
  passed, and control dependencies are created.
  .. code-block:: python
  +
  ...
  results = embedded_runtime.embedded_runtime_call(
  call_inputs, context)
  @@ -61,6 +63,7 @@ can outlive the TensorFlow session.
  Pipelining and I/O tiles
  ~~~~~~~~~~~~~~~~~~~~~~~~
  +
  When running a pipelined application, or an application with I/O tiles, we must
  handle the additional layer of pipelining. This is a result of there being
  multiple batches of data resident in the device at the same time.
  @@ -96,6 +99,7 @@ utilisation of the devices and minimises the batch latency.
  Timeout
  _______
  +
  When the application is pipelined or using I/O tiles, and data starvation might
  occur, the timeout option allows you to set an upperbound on the time the IPU
  will wait for data.
  @@ -113,6 +117,7 @@ device. This unblocks any pending batches that are in the device.
  Engine restarts
  _______________
  +
  The number of batches to process in an application is a compile-time decision.
  However, you might later deliver more batches at runtime than compiled for. If
  this happens, the Poplar engine will be restarted. A restart blocks enqueued
  @@ -131,6 +136,7 @@ choose a value large enough to minimise this.
  Example
  ~~~~~~~~
  +
  This example creates a very simple IPU program that doubles the input tensor.
  .. literalinclude:: embedded_application_runtime_example.py
  @@ -149,7 +155,7 @@ Error Handling
  :ref:`xla_runtime_error_handling`.
  Runtime errors
  -..............
  +______________
  These errors and exceptions occur when running a Poplar program. The full list
  of all the exceptions and their meanings can be found in the Poplar
  