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

**Use case**
People are used to Postgres.
if (std::is_same_v<Collection, Tuple> && arr.size() == 1)
                    return false;
                literal = std::make_shared<ASTLiteral>(arr);
                literal->begin = literal_begin;
                literal->end = ++pos;
                node = literal;
                return true;
            }
            else if (pos->type == TokenType::Comma)
            {
                ++pos;
            }
            else
            {
                expected.add(pos, "comma or closing bracket");
                return false;
            }
        }
        ASTPtr literal_node;
        if (!literal_p.parse(pos, literal_node, expected) && !collection_p.parse(pos, literal_node, expected))
            return false;
        arr.push_back(literal_node->as<ASTLiteral &>().value);
    }
    expected.add(pos, getTokenName(closing_bracket));
    return false;
}
template bool ParserCollectionOfLiterals<Array>::parseImpl(Pos & pos, ASTPtr & node, Expected & expected);
template bool ParserCollectionOfLiterals<Tuple>::parseImpl(Pos & pos, ASTPtr & node, Expected & expected);
bool ParserLiteral::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)