Comment 0 for bug 423733

The code assumes that if there is less than 30 days to go it only needs to output one month.
The linked branch has a fix where it really checks the amount of days in the coming month.

There might be a problem in that file as i see the code constantly using lengthmonth(year,month+i) + 1
Not sure why the +1 is there. I have duplicated this behaviour though not 100% sure if that is correct but my test case now comes out perfectly.