Deprecate PDO::ATTR_ERRMODE [Proposed RFC]

Hi, internals. I thought about various things to improve the current situation where PDO::ATTR_ERRMODE is not working very smartly. Exceptions may be thrown regardless of the setting of PDO::ATTR_ERRMODE. https://www.php.net/manual/en/pdo.rollback.php#refsect1-pdo.rollback-errors Another annoyance is that PDO::ERRMODE_SILENT sometimes gives a warning. This is an undocumented phenomenon, and it's a 19-year-old vintage bug. https://github.com/php/php-src/blob/223fb08819967b3063610289a5783944a85d6d65/ext/pdo/pdo_dbh.c#L74 Based on these, I feel that the reliability of the attribute value PDO::ATTR_ERRMODE is low and there is not much meaning in its existence as an attribute value. Since the default behavior became PDO::ERRMODE_EXCEPTION in PHP8.0.0, I think it would be better to abolish it rather than leave it halfway. I think this is a big change, so I'm assuming 9.x+ even if it's implemented. I will do the implementation myself. Please let me know what you think. Thank you. Saki