Feature Request: Support for Levantine Arabic month names in intl package

Hello intl team 👋,

First, thank you for your great work on the intl package.

Currently, when using DateFormat.MMMM('ar'), the month names are shown as:

• يناير, فبراير, مارس … ديسمبر

This is correct for Modern Standard Arabic and commonly used in many Arabic-speaking regions.
However, in the Levant (Syria, Lebanon, Palestine, Jordan, parts of Iraq), the traditional month names are different, for example:

• كانون الثاني, شباط, آذار, نيسان, أيار, حزيران, تموز, آب, أيلول, تشرين الأول, تشرين الثاني, كانون الأول

These names are still widely used in everyday life, newspapers, and even in official documents across the Levant region.

Suggestion:

• Add support for an additional Arabic locale (e.g., ar-SY or ar-LB) that uses these month names.
• Alternatively, provide an option or extension mechanism in intl to override the default month names for specific regional Arabic locales.

This would improve localization for millions of Arabic speakers in the Levant region.

Thank you for considering this request 🙏