pub fn split_cells(body: &str) -> Vec<String>Expand description
Split body on lines containing only +++ (after trim) into cells.
Returns at least one cell — a body with no divider produces a single-element vector containing the full body. Surrounding newlines inside each cell are preserved verbatim except for the divider line itself.
The match is strict: a line must trim to exactly "+++". Variants
like ++++ or + + + or trailing comment text on the same line do
NOT count, mirroring how CommonMark handles --- thematic breaks
vs. setext headings.