Fix bug

Fixed bug that the root coroutines were not removed from the active list once they finished.

src/CoroutineBase.cs

@@ -35,6 +35,8 @@ public class CoroutineBase
     /// Determines the pause behaviour of this coroutine.
     /// </summary>
     public CoRunMode RunMode { get; private set; }
+
+    public event Action Stopped;
 
     public void StartCoroutine(CoroutineBase coroutine)
     {
@@ -191,6 +193,7 @@ public void Kill()
         }
 
         Parent?.OnChildStopped(this);
+        Stopped?.Invoke();
     }
 
     /// <summary>

src/CoroutineManager.cs

@@ -24,6 +24,7 @@ public partial class CoroutineManager : Node
     public void StartCoroutine(CoroutineBase coroutine)
     {
         coroutine.Manager = this;
+        coroutine.Stopped += () => aliveRootCoroutines.Remove(coroutine);
         coroutine.Init();
         aliveRootCoroutines.Add(coroutine);
     }