Align native union type order with docblocks

[dereuromark]

Summary

• Sort native function parameter and return union types with the existing PhpCollective.Commenting.TypeHint order.
• Keep docblock and native examples aligned for cases like string|int vs int|string.
• Document the shared union type order behavior.

Checks run

• composer cs-fix
• composer cs-check
• composer test
• composer stan