add ability to mark some days on the calendar

[karam1ashqar]

can be called calendarMarkedDateIds and DayState of "marked" and behave like the current calendarDisabledDateIds and "disabled" DayState

[MarceloPrado]

For now, I'm afraid I won't build this feature - it goes against the first principle: Solve fewer needs better.

Adding marked day support adds new considerations such as:

• What's the difference between a marked and an active day?
• Can a day be both marked and active? How is that represented?

For this feature, I'd suggest you to compose your own calendar as recommended by the docs here 🙂