Add reasoning_content field to ChatCompletionMessageForResponse

Author: Lin,xiaolong

src/v1/chat_completion.rs

@@ -228,6 +228,8 @@ pub struct ChatCompletionMessageForResponse {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub content: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
+    pub reasoning_content: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub tool_calls: Option<Vec<ToolCall>>,