添加对象池并更新KeySettingManager的README

Pool/README.md

@@ -0,0 +1,42 @@
+新建一个对象池类继承SingletonObjectPool后，在UnityEditor中会自动创建以类名为名称的单例实例。
+```csharp
+public class EnemyPool : SingletonObjectPool<Enemy>
+{
+}
+```
+用法示例如下方刷怪圈
+```csharp
+public class EnemySpawner : MonoBehaviour
+{
+    public GameObject enemyPrefab;
+    public int initialPoolSize = 5;
+    public int maxPoolSize = 10;
+    public float spawnInterval = 3f;
+    public int spawnCount = 1;
+    public float spawnRadius = 5f;
+
+    private void Start()
+    {
+        SingletonObjectPool<Enemy>.Instance.Init(enemyPrefab.GetComponent<Enemy>(), initialPoolSize, maxPoolSize);
+        StartCoroutine(SpawnEnemiesCoroutine());
+    }
+
+    private IEnumerator SpawnEnemiesCoroutine()
+    {
+        while (true)
+        {
+            yield return new WaitForSeconds(spawnInterval);
+            SpawnEnemies();
+        }
+    }
+
+    private void SpawnEnemies()
+    {
+        for (var i = 0; i < spawnCount; i++)
+        {
+            var spawnPosition = transform.position + (Vector3)Random.insideUnitCircle * spawnRadius;
+            SingletonObjectPool<Enemy>.Instance.Spawn(transform).transform.position = spawnPosition;
+        }
+    }
+}
+```