message: Fix docs for 'Accumulation data type'
  Summary:
  Fix wrong section type.
  Ref. T27846.
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, georgep
  Maniphest Tasks: T27846
diff: @@ -316,7 +316,7 @@ gone through the whole model pipeline.
  .. _optimiser-state-unloading:
  Accumulation data type
  -----------------------
  +______________________
  When accumulating gradients over a large number of mini-batches, it can be
  beneficial to perform the accumulation in a data type with higher precision
  