Fix LayoutRunIter returning lines beyond Buffer height

src/buffer.rs

@@ -130,7 +130,7 @@ impl<'b> Iterator for LayoutRunIter<'b> {
                 let centering_offset = (line_height - glyph_height) / 2.0;
                 let line_y = line_top + centering_offset + layout_line.max_ascent;
                 if let Some(height) = self.buffer.height_opt {
-                    if line_top + centering_offset > height {
+                    if line_y > height {
                         return None;
                     }
                 }