Bug when setting up WordPress with a single quote in the database user password

[djule5]

When setting up WordPress, if a single quote exists in the user password, a PHP parse error will follow because the wp-config will be written in a corrupted state. Example below:

define('DB_PASSWORD', '@Qp!G$AfPgoCo'm7pjK9');

Same kind of issue can happen if using backslashes.

The setup should either escape single quotes and backslashes or disallow the use of these characters.

[SergeyBiryukov]

#13839