use correct ds doc syntax

lua/plugins/avante_202507.lua

@@ -23,7 +23,7 @@ return {
         __inherited_from = "openai",
         api_key_name = "DEEPSEEK_API_KEY",
         endpoint = "https://api.deepseek.com",
-        model = "deepseek-coder",
+        model = "deepseek-chat",
         disable_tools = false,
       },
     },