Add automatic AM/PM logic

[squatto]

It is 3:25pm where I live, and if I do r at 4:30 Go home it sets a reminder at 4:30am tomorrow morning. The date parsing library is interpreting it correctly, albeit a bit too literal. I have to do r at 16:30 or r at 4:30 tonight to get it to work as intended. The same thing happens if I do r at 3:45 - even though that is in 20 minutes, it interprets it as tomorrow morning at 3:45am.

It would be helpful to add some logic that determines the nearest future hour instead of parsing it literally. I think the conditions would be:

1. It is currently PM
2. No AM/PM is specified in the command
3. The provided hour is between 0 and 12
4. The provided hour is >= the current hour

The Chrono docs actually has a code snippet in the "Refiner" section that does something very similar:

https://github.com/wanasit/chrono/blob/b6140ec17996fec84c790891ecbfd8b7d44fbb5b/README.md#L218-L245

---

// In the example, the custom refiner assigns PM to parsing results with ambiguous meridiem (http://en.wikipedia.org/wiki/12-hour_clock).

const custom = chrono.casual.clone();
custom.refiners.push({
    refine: (context, results) => {
        // If there is no AM/PM (meridiem) specified,
        //  let all time between 1:00 - 4:00 be PM (13.00 - 16.00)
        results.forEach((result) => {
            if (!result.start.isCertain('meridiem') &&
                result.start.get('hour') >= 1 && result.start.get('hour') < 4) {

                result.start.assign('meridiem', 1);
                result.start.assign('hour', result.start.get('hour') + 12);
            }
        });
        return results;
    }
});

// This will be parsed as PM.
// > Tue Dec 16 2014 14:30:00 GMT-0600 (CST) 
custom.parseDate("This is at 2.30");

// Unless the 'AM' part is specified
// > Tue Dec 16 2014 02:30:00 GMT-0600 (CST)
custom.parseDate("This is at 2.30 AM");

---

With a little bit of tweaking, I think that could do exactly what I'm talking about. If you'd like, I'd be happy to PR the change. It will likely be a couple of weeks from now, but I'd be happy to.

Thanks for such an amazing workflow! It's indispensable to my daily routine.