#2964: document break_lines

crates/layout/src/para.rs

@@ -1884,6 +1884,8 @@ fn ptab_stop(align: PTabAlign, base: PTabBase, leader: TabLeader, width: f32, in
     TabStop { pos, align, leader }
 }
 
+/// Break a paragraph into lines, measure each line, apply the paragraph's alignment and place
+/// the list label. Fills `pl.lines`, `pl.height` and the label's position.
 fn break_lines(pl: &mut ParaLayout, env: &ParaEnv, mark_style: u32, level: Option<&Level>) {
     // Narrow cells and float spans must retain their usable width.
     const MIN_LINE_WIDTH: f32 = 1.0;