[editorial] Invalid URL for MariaDB error code reference

[vitorvasc]

The following link used in the docs/db/mariadb.md and docs/db/sql.md pages is currently returning an HTTP 500 error:

• MariaDB error code reference: https://mariadb.com/kb/en/mariadb-error-code-reference/

This URL appears in:

• docs/db/mariadb.md - in the db.response.status_code attribute note
• docs/db/sql.md - in the db.response.status_code attribute note listing vendor-specific error codes

Would this link be a valid replacement? https://mariadb.com/docs/server/reference/error-codes