reconfigure({ locale, numberingSystem, outputCalendar } = {}) {
    const loc = this.loc.clone({ locale, numberingSystem, outputCalendar });
    return clone(this, { loc });
  }
"Set" the locale, numberingSystem, or outputCalendar. Returns a newly-constructed DateTime.
@param {Object} properties - the properties to set
@example DateTime.local(2017, 5, 25).reconfigure({ locale: 'en-GB' })
@return {DateTime}