The introduction for each individual test looked like an actual
command:

  test-subtree
  ./release-tools/verify-subtree.sh release-tools
  Directory 'release-tools' contains non-upstream changes:
  ...

It's better to make it look like a shell comment and increase its
visibility with a longer prefix:

  ### test-subtree:
  ./release-tools/verify-subtree.sh release-tools
  ...