Two specific mismatches between docs and runtime behavior need resolution.

Mismatch 1: ONLY option

• Docs: knex(table, { only: true }) / .from(..., { only: true }) are PostgreSQL-only.
• Code: emits ONLY for all dialects.

Mismatch 2: skipLocked on MariaDB

• Docs: .skipLocked() supports MariaDB 10.6+.
• Code: skipLocked is implemented only for MySQL and PostgreSQL; comments mention MariaDB only for .noWait().

We should:

1. Decide whether to update code or docs for the ONLY option.
2. Confirm MariaDB SKIP LOCKED support and either implement it or update docs.
3. Add regression tests for both cases