feat(templates): avanterules filetype support (closes #254) (#466)

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>

lua/avante/providers/init.lua

@@ -10,7 +10,7 @@ local Dressing = require("avante.ui.dressing")
 ---
 ---@class AvantePromptOptions: table<[string], string>
 ---@field system_prompt string
----@field user_prompts string[]
+---@field user_prompt string
 ---@field image_paths? string[]
 ---
 ---@class AvanteBaseMessage
@@ -70,6 +70,7 @@ local Dressing = require("avante.ui.dressing")
 ---@field has fun(): boolean
 ---@field api_key_name string
 ---@field tokenizer_id string | "gpt-4o"
+---@field use_xml_format boolean
 ---@field model? string
 ---@field parse_api_key fun(): string | nil
 ---@field parse_stream_data? AvanteStreamParser
@@ -275,6 +276,10 @@ M = setmetatable(M, {
       t[k].tokenizer_id = "gpt-4o"
     end
 
+    if t[k].use_xml_format == nil then
+      t[k].use_xml_format = false
+    end
+
     if t[k].has == nil then
       t[k].has = function()
         return E.parse_envvar(t[k]) ~= nil