Provide intermediate feedback during property test runs.

Avoid the interface to hang for several seconds without feedback when counterexamples are being simplified. This sends a heads-up to the user to indicate that a research of a counter example is going on.

crates/aiken-project/src/telemetry.rs

@@ -168,7 +168,7 @@ impl EventListener for Terminal {
             }
             Event::RunningTests => {
                 eprintln!(
-                    "{} {}\n",
+                    "{} {}",
                     "      Testing"
                         .if_supports_color(Stderr, |s| s.bold())
                         .if_supports_color(Stderr, |s| s.purple()),
@@ -205,7 +205,7 @@ impl EventListener for Terminal {
 
                     let summary = format!("{}{}", seed_info, fmt_test_summary(results, true));
                     println!(
-                        "{}\n",
+                        "\n{}",
                         pretty::indent(
                             &pretty::open_box(&title, &tests, &summary, |border| border
                                 .if_supports_color(Stderr, |s| s.bright_black())
@@ -214,6 +214,10 @@ impl EventListener for Terminal {
                         )
                     );
                 }
+
+                if !tests.is_empty() {
+                    println!();
+                }
             }
             Event::ResolvingPackages { name } => {
                 eprintln!(