docs(rtk-query): add headers argument to base query example using axios

Author: reza-sadeghzadeh

docs/rtk-query/usage/customizing-queries.mdx

@@ -369,16 +369,17 @@ const axiosBaseQuery =
       method: AxiosRequestConfig['method']
       data?: AxiosRequestConfig['data']
       params?: AxiosRequestConfig['params']
+      headers?: AxiosRequestConfig['headers']
     },
     unknown,
     unknown
   > =>
-  async ({ url, method, data, params }) => {
+  async ({ url, method, data, params, headers }) => {
     try {
-      const result = await axios({ url: baseUrl + url, method, data, params })
+      const result = await axios({ url: baseUrl + url, method, data, params, headers })
       return { data: result.data }
     } catch (axiosError) {
-      let err = axiosError as AxiosError
+      const err = axiosError as AxiosError
       return {
         error: {
           status: err.response?.status,