Clarify granularity level of dayStartTime and dayEndTime in API docs

[ExtAnimal]

Forum post

We pushed our latest release live on Sunday, with the latest Calendar release, but had to pull it due to complaints from users. The time-rule and the event start times are out of whack.

Images attached.

let calendarDate = calendar.date
    const day = new Date(calendarDate).getDay();
    const dayNames = ["sun", "mon", "tue", "wed", "thu", "fri", "sat"];
    const data =  dmx.parse('_opening_hours.data._list.open_hours')
     calendar.activeView.view.dayStartTime = data[dayNames[day]+"_open"]
     calendar.activeView.view.dayEndTime = data[dayNames[day]+"_close"]