Add StripBuilder::sense & TableBuilder::sense

[aleokdev]

Closes #1553.

[emilk]

Adding a sense is good, but I think we should add a hover effect to it as well. Everything clickable in egui changes appearance when you hover it. This is what let's you know you can click it. You can follow this pattern:

if sense.click || sense.drag {
    let visuals = ui.style().interact(&response);
    ui.painter().rect(
        rect.expand(visuals.expansion),
        visuals.rounding,
        visuals.bg_fill,
        visuals.bg_stroke,
    );
}

[aleokdev]

Not too sure about how to do that. 😅 I've tried to put that in StripLayout::add after the rect allocation, using the allocated rect as the rect to use in the painter, but I just get entire rectangles:

I'm not too sure how strips work internally either. Will need to dive into this a bit further.

[emilk]

Ideally it should be drawn behind the row, but that's harder because #1516 isn't done yet. There is a hack for it, by using painter.add(Shape::Noop) (see egui::Frame for example).

[emilk]

• Feature implemented in Implement table row selection and hover highlighting #3347