`INTERVAL '1 hour'` should be equivalent to `INTERVAL 1 HOUR`

**Use case**
People are used to Postgres.
{
    ASTPtr id_list;
    if (!ParserList(std::make_unique<ParserIdentifier>(), std::make_unique<ParserToken>(TokenType::Dot), false)
        .parse(pos, id_list, expected))
        return false;
    String name;
    std::vector<String> parts;
    const auto & list = id_list->as<ASTExpressionList &>();
    for (const auto & child : list.children)
    {
        if (!name.empty())
            name += '.';
        parts.emplace_back(getIdentifierName(child));
        name += parts.back();
    }
    ParserKeyword s_uuid("UUID");
    UUID uuid = UUIDHelpers::Nil;
    if (table_name_with_optional_uuid && parts.size() <= 2 && s_uuid.ignore(pos, expected))
    {