message: docs(aio): fix numbered list in testing.md
  This list renders OK in the github UI but not at
diff: @@ -160,6 +160,7 @@ This guide describes specific choices that are known to work well.
  ### Setup
  There are two fast paths to getting started with unit testing.
  +
  1. Start a new project following the instructions in [Setup](guide/setup "Setup").
  1. Start a new project with the
  