message: Fix Markdown table format to dispay correctly on GitHub
  GitHub requires a leading | for tables.
diff: @@ -24,10 +24,10 @@ the codegen input.
  ## Tasks
  - | Host | Device
  -------------- | ------------------------ | ------------------------
  -Input format | HloInstruction* (Task 1) | HloInstruction* (Task 1)
  -Output format | xla::Thunk (Task 2) | LLVM IR (Task 3)
  +| | Host | Device
  +| ------------- | ------------------------ | ------------------------
  +| Input format | HloInstruction* (Task 1) | HloInstruction* (Task 1)
  +| Output format | xla::Thunk (Task 2) | LLVM IR (Task 3)
  * **Task 1** changes both host and device input format from HloInstruction* to
  LHLO.
  