Interval#count incorrectly includes the end-point

[diesieben07]

Describe the bug
The Interval documentation states that

An Interval object represents a half-open interval of time

To me this means that the interval includes the starting point, but not the end point. This is confirmed by checking interval.contains(interval.end), which always returns false. However Interval#count also counts the endpoint.

To Reproduce

const {Interval, DateTime} = require('luxon');

const startDate = DateTime.fromISO("2022-10-01T00:00:00.000+02:00");
const interval = Interval.after(startDate, {days: 2});

console.log(interval.contains(interval.end)); // as expected this is false
console.log(interval.count('days')); // this reports 3, but the interval only contains 2 calendar days (1st and 2nd)
console.log(interval.length('hours')); // as expected this reports exactly 48, because the first millisecond of the 3rd is not included

See here: https://runkit.com/embed/xxwq2ofg22di

Actual vs Expected behavior
Interval#count should not count the interval's endpoint.

Desktop (please complete the following information):

• OS: Linux Mint
• Browser: Chrome 106, also happens on Node 14
• Luxon version: 3.0.4
• Your timezone: Europe/Berlin

Additional context
Looking at the code for count, it unconditionally adds 1 to the result of diffing start and end. This addition must only be done if end is actually different from end.startOf(unit).