pub fn char_marks(a: &[char], b: &[char]) -> Option<(Vec<bool>, Vec<bool>)>Expand description
Character-level marks per FR-117: Some((changed_in_a, changed_in_b)) with one bool per char,
or None when the pair exceeds CHAR_DIFF_MAX_CHARS or MYERS_MAX_EDITS (whole block changed, no highlight).