docs: 修正缓存 plan 中 Mockito API 笔误(openMocks→initMocks,适配项目 3.3.3)

docs/superpowers/plans/2026-06-25-redis-cache.md

@@ -546,7 +546,7 @@ class RedisCacheEnhanceTemplateTest {
 
     @BeforeEach
     void init() {
-        MockitoAnnotations.openMocks(this);
+        MockitoAnnotations.initMocks(this);
         lenient().when(redis.opsForValue()).thenReturn(valueOps);
         template = new RedisCacheEnhanceTemplate(redis, keyBuilder, codec, props);
     }