first
Returns the first day of the year-month.
Samples
import kotlinx.datetime.*
import kotlinx.datetime.format.*
import kotlinx.datetime.onDay
import kotlin.test.*
fun main() {
//sampleStart
// Getting the first and last day of a year-month
val yearMonth = YearMonth(2024, Month.FEBRUARY)
check(yearMonth.firstDay == LocalDate(2024, Month.FEBRUARY, 1))
check(yearMonth.lastDay == LocalDate(2024, Month.FEBRUARY, 29))
//sampleEnd
}