Add log for soft limit reach, tweak values, clippy

src/search/iterative_deepening.rs

@@ -18,6 +18,7 @@ pub fn iterative_deepening(
 
     for depth in 1..=max_depth {
         if time.exceed_soft_limit() {
+            write_response(&mut io::stdout(), &Response::Info("Soft limit exceeded in negamax".to_string()))?;
             return Ok(best_move);
         }