pub fn month_grid(month: Date, start: Weekday) -> [Date; 42]Expand description
The block a month is drawn in: 42 real dates, beginning on the start
weekday on or before the 1st.
Six rows even for a February that fits in four, so the card never changes
height as you page months — a popover that resizes under the pointer moves
the day you were about to click. Leading and trailing cells are real dates
from the neighbouring months rather than blanks, which makes
cell.month() != month.month() the only test a cell needs and leaves
clicking one meaningful.