docs: Fix containers module documentation discrepancies

- Array::SetAllocator: Remove reference to non-existent PoolAllocator class
- HashMap::SetAllocator: Remove reference to non-existent GetDefaultAllocator()
- HashMap::Copy/Move: Fix move constructor complexity (O(m_bucketCount), not O(1))
- HashMap::iterator: Remove C++20 structured bindings example
- String: Add missing links for operator+ and operator==/!=

docs/api/containers/hashmap/copy-move.md

@@ -14,7 +14,7 @@ HashMap(HashMap&& other) noexcept;
 
 **复杂度：**
 - 拷贝构造：O(m_bucketCount + other.m_size)
-- 移动构造：O(1)，直接接管源对象的内部资源
+- 移动构造：O(m_bucketCount)，移动构造需要遍历所有桶以重新建立桶的指针关系
 
 **示例：**