Aint Workin for Calendars ending on Sunday

[OmarGardener]

Switching between months showed, that a couple of months, f.e. October 2020, ain't rendering at all.

script.js:
Shoving " monthDays.innerHTML = days;" from line 68 to below the for loop will do the trick.

[alpzaf]

Replacing "const nextDays = 7 - lastDayIndex -1;" ==> " const nextDays = 7 - lastDayIndex;" will solve the problem with calendars which are ending on Sunday