fix: select the same day in range mode when range is open and min prop is 0

[rodgobbi]

Fixes #2813

[gpbl]

Nice, thanks!

I'm not convinced by the RangeResetSelection example: while it reproduces the bug's use case, it's not very clear.

I would have implemented the example starting with an open range:

export function OpenRange() {
  const [range, setRange] = useState<DateRange | undefined>({
    from: new Date(),
    to: undefined,
  });

  let footer = `Please pick the first day.`;
  if (range?.from) {
    if (!range.to) {
      footer = range.from.toLocaleDateString();
    } else {
      footer = `${range.from.toLocaleDateString()}—${range.to.toLocaleDateString()}`;
    }
  }

  return (
    <DayPicker
      mode="range"
      selected={range}
      onSelect={setRange}
      footer={footer}
    />
  );
}

The test description could be:

When the initial selected range is open, clicking the start of the range should close the range.

I’m also not sure the test is necessary, since it appears to be already covered by addToRange.test.ts.

I suggest either removing the example or updating it to something simpler, like the example above.

Aside:

• We’ve never explicitly used the terms “open” or “closed” range in our code, but I think they fit well.
• It might be worth investigating whether we can deprecate the DateRange type and adopt the date-fns DateInterval instead. I’ve added this idea to the backlog.