Steffen Becker
d26fcae94d
A heading whose successor no longer fits below it was left stranded at the page foot; Word and LibreOffice move it down with them, which is why their heading styles all carry w:keepNext / fo:keep-with-next. Headings do it by default here, so the attr only marks the other blocks that ask for it. One level deep: a run of kept-together blocks would need the pagination pass to reconsider leaves it has already placed.