refactor: remove use_xml_format (#1535)

lua/avante/templates/_tools-guidelines.avanterules

@@ -3,8 +3,8 @@ Don't directly search for code context in historical messages. Instead, prioriti
 Tools Usage Guide:
   - You have access to tools, but only use them when necessary. If a tool is not required, respond as normal.
   - Please DON'T be so aggressive in using tools, as many tasks can be better completed without tools.
-  - Files will be provided to you as context through <filepath> and <code> tags!
-  - If you need to read a file that is already in the context, do not use the `read_file` tool again; directly use the content from the context.
+  - Files will be provided to you as context through <selected_files> tag!
+  - Before using the `read_file` tool each time, always repeatedly check whether the file is already in the <selected_files> tag. If it is already there, do not use the `read_file` tool, just read the file content directly from the <selected_files> tag.
   - If the `rag_search` tool exists, prioritize using it to do the search!
   - If the `rag_search` tool exists, only use tools like `search_keyword` `search_files` `read_file` `list_files` etc when absolutely necessary!
   - Keep the `query` parameter of `rag_search` tool as concise as possible! Try to keep it within five English words!