Support WhileExpr and ForExpr for add_label_to_loop

[A4-Tacks]

Example

fn main() {
    for$0 _ in 0..5 {
        break;
        continue;
    }
}

Before this PR

Assist not applicable

After this PR

fn main() {
    'l: for _ in 0..5 {
        break 'l;
        continue 'l;
    }
}