Connection::query() return types missing string

The docblock for Connection::query() has the return definition set to @return \Drupal\Core\Database\StatementInterface|int|null. However, there is also the statement return $this->connection->lastInsertId($sequence_name);. $this->connection is defined as @var \PDO and php.org defines the function as public PDO::lastInsertId ([ string $name = NULL ] ) : string.

The return definition should be changed to @return \Drupal\Core\Database\StatementInterface|int|string|null.

This error was flagged by the mglaman/drupal-check tool.

The entire original return section is as follows:

    * @return \Drupal\Core\Database\StatementInterface|int|null
   *   This method will return one of the following:
   *   - If either $options['return'] === self::RETURN_STATEMENT, or
   *     $options['return'] is not set (due to self::defaultOptions()),
   *     returns the executed statement.
   *   - If $options['return'] === self::RETURN_AFFECTED,
   *     returns the number of rows affected by the query
   *     (not the number matched).
   *   - If $options['return'] === self::RETURN_INSERT_ID,
   *     returns the generated insert ID of the last query.
   *   - If either $options['return'] === self::RETURN_NULL, or
   *     an exception occurs and $options['throw_exception'] evaluates to FALSE,
   *     returns NULL. 

We will update one section to:

  *   - If $options['return'] === self::RETURN_INSERT_ID,
   *     returns the generated insert ID of the last query as a string.