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]`.
{
    
    fs::path datadir = GetDataDir();
    if (!DirIsWritable(datadir)) {
        return InitError(strprintf(_("Cannot write to data directory '%s'; check permissions."), datadir.string()));
    }
    if (!LockDirectory(datadir, ".lock", probeOnly)) {
        return InitError(strprintf(_("Cannot obtain a lock on data directory %s. %s is probably already running."), datadir.string(), _(PACKAGE_NAME)));
    }
    return true;
}
bool AppInitSanityChecks()