Function pluralFor

pluralFor(
    language: string,
    count: number,
    forms: PluralForms,
    extra?: Readonly<Record<string, string | number>>,
): string
Picks the right plural form for count in language and interpolates it.

Uses Intl.PluralRules for the CLDR category, then substitutes {count} and anything in extra.
Parameters
- language: string
- count: number
- forms: PluralForms
- Optionalextra: Readonly<Record<string, string | number>>
Returns string
Example
```
pluralFor('en', 1, { one: '{count} item', other: '{count} items' });
// '1 item'
pluralFor('en', 3, { one: '{count} of {total}', other: '{count} of {total}' }, { total: 10 });
// '3 of 10'
```
- Defined in src/capabilities/l10n/format.ts:128