method Intl.DateTimeFormat.formatRange
          
DateTimeFormat.formatRange<T extends Formattable>(startDate: T,endDate: T,): string 
      Format a date range in the most concise way based on the locale and
options provided when instantiating this `Intl.DateTimeFormat` object.
  
  
    
 
   
  
  
    
 
T extends Formattable
      
    string