update ext-storage\api.md

docs/uniCloud/ext-storage/api.md

@@ -22,11 +22,11 @@
 
 ## 开通扩展存储服务@open
 
-参考[开通服务](uniCloud/uni-cloud-ext-storage/open.md)
+参考[开通服务](uniCloud/ext-storage/open.md)
 
 ## 费用说明@price
 
-参考[费用说明](uniCloud/uni-cloud-ext-storage/price.md)
+参考[费用说明](uniCloud/ext-storage/price.md)
 
 ## 为云函数启用uni-cloud-ext-storage扩展库@use-in-function