feat(cache): improve md (#1063)

Co-authored-by: 彭业昌 <[email protected]>

website/docs/jupiter/4.9freecache.md

@@ -53,6 +53,7 @@ pkg/cache 包支持多个本地缓存库，并支持metric上报
 ### 2 初始化实例
 ```go
 import (
+	"github.com/douyu/jupiter/pkg/cache"
     "github.com/douyu/jupiter/pkg/cache/xfreecache/v2"
 )
 
@@ -62,7 +63,7 @@ type Student struct {
 }
 
 type Instance struct {
-	localCache *xfreecache.LocalCache[string, Student]
+	localCache *cache.Cache[string, Student]
 }
 
 func NewInstance() *Instance {
@@ -134,11 +135,12 @@ package bwlist
 
 import (
 	"context"
+	"github.com/douyu/jupiter/pkg/cache"
 	"github.com/douyu/jupiter/pkg/cache/xfreecache/v2"
 )
 
 type Instance struct {
-	localCache *xfreecache.LocalCache[int32, []int32]
+	localCache *cache.Cache[int32, []int32]
 }
 
 func NewInstance() *Instance {