name: A closing marker written across a multi-line comment closes the region
why: The closing marker is recognized when its comment closes rather than when it opens, since until then the comment's content is not known. Pinned separately from the opening form because the closing one is read from inside an open region, where every line is otherwise passing through untouched, and an implementation can arm one without ever reaching the other. The paragraph after the marker unwraps as usual, which is what says the region really ended.
paragraphs_unwrapped: 1
line_breaks_removed: 1
