Function paint_find_match 

pub fn paint_find_match(
    scene: &mut Scene,
    transform: Affine,
    rect: Rect,
    current: bool,
    theme: &Theme,
)

Paint one match highlight over rect, the span of the matched glyphs — never a whole line or block. Every match is a wash of the searcher’s own selection colour; the current one is stronger and outlined so it can be told apart at a glance.