Suggested by @MarcoFalke after #14627 and possibly #14420. We should warn if an unrecognised/incorrect section is present in bitcoin.conf. i.e `[testnet]` is present instead of `[test]`.
{
    std::vector<std::string> result = {};
    if (IsArgNegated(strArg)) return result; 
    LOCK(cs_args);
    ArgsManagerHelper::AddArgs(result, m_override_args, strArg);
    if (!m_network.empty()) {
        ArgsManagerHelper::AddArgs(result, m_config_args, ArgsManagerHelper::NetworkArg(*this, strArg));
    }
    if (ArgsManagerHelper::UseDefaultSection(*this, strArg)) {
        ArgsManagerHelper::AddArgs(result, m_config_args, strArg);
    }
    return result;
}
bool ArgsManager::IsArgSet(const std::string& strArg) const
{
    if (IsArgNegated(strArg)) return true; 
    return ArgsManagerHelper::GetArg(*this, strArg).first;
}
bool ArgsManager::IsArgNegated(const std::string& strArg) const