build: clarify missing clang-format tool
This confused me when I had to run make format-cpp. Clarify that it's not clang-format itself that's missing but rather some tooling around that.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This confused me when I had to run make format-cpp. Clarify that it's not clang-format itself that's missing but rather some tooling around that.