emitNegatableFlag function
A negatable flag, emitted explicitly in both directions.
Always explicit, because the baked-in command outlives the default that
produced it: --ship-logs defaults to true today, and a service installed
with --no-ship-logs must keep shipping nothing even if that default flips.
Implementation
void emitNegatableFlag(List<String> out, String name, bool value) =>
out.add(value ? '--$name' : '--no-$name');