docs(feign client): sync docs from DaprInvokeFeignClient

docs/en/feign/getting-started.md

@@ -83,6 +83,8 @@ For invokeBinding, the URL also contains two types of information: the host is t
 
 As for the response, the result code is always 200 OK. If the client encounters any errors, it will throw an IOException.
 
+Currently, we have no method to gain metadata from server as Dapr Client doesn't have methods to do that, so headers will be blank. If Accept header has set in request, a fake Content-Type header will be created in response, and it will be the first value of Accept header.
+
 ## Other
 
 For more usage methods, please refer to other entries in the [homepage](../index.md), and consult the [configuration](configuration.md) entry to configure parameters.

docs/zh-CN/feign/getting-started.md

@@ -83,6 +83,8 @@ feign-dapr-client是独立于Spring Boot的工件，没有引入dapr-spring-boot
 
 至于响应，结果代码始终是200 OK，如果客户端遇到任何错误，它将抛出一个IOException。
 
+当前，我们无法从服务器获取元数据，因为Dapr客户端没有这样做的方法，所以HTTP响应头将为空。如果请求中设置了Accept请求头，那么在响应中将创建一个假的Content-Type响应头，并且它将是Accept请求头的第一个值。
+
 ## 其他
 
 请参阅[主页](../index.md)中的其他条目来获取更多使用方式，请参阅[配置](configuration.md)条目对参数进行配置。