Support Intl.ListFormat

[dilyanpalauzov]

Introduce types for Intl.ListFormat. The code below shall not generate errors:

new Intl.ListFormat('bg', {type: 'conjunction'}).format(['a','b','c'])

[RyanCavanaugh]

To expedite the triage process, we need everyone to follow the issue template and instructions.

When you clicked "Create New Issue", the issue form was pre-populated with a template and some instructions. We need you to read those instructions completely, follow them, and then fill in all the fields in that template.

We are not able to assist with issues that don't follow the template instructions as they represent a significantly larger amount of work compared to issues which are correctly specified. Thank you for understanding.