message: Fix quotation typo around "task"
diff: @@ -48,7 +48,7 @@ class MirroredStrategy(distribute_lib.DistributionStrategy):
  distributed environment.
  There are several important concepts for distributed TensorFlow, e.g.
  - `client`, `job`, 'task', `cluster`, `in-graph replication` and
  + `client`, `job`, `task`, `cluster`, `in-graph replication` and
  'synchronous training' and they have already been defined in the
  [TensorFlow's documentation](https://www.tensorflow.org/deploy/distributed).
  The distribution strategy inherits these concepts as well and in addition to
  