Doc:update wifi api docs

* Add documents related to espnow config rate

* Optimization set dns server api description

components/esp_netif/include/esp_netif.h

@@ -619,9 +619,10 @@ esp_err_t esp_netif_dhcps_stop(esp_netif_t *esp_netif);
  *
  *   If DHCP server is enabled, the Main DNS Server setting is used by the DHCP server to provide a DNS Server option
  *   to DHCP clients (Wi-Fi stations).
- *   - The default Main DNS server is typically the IP of the Wi-Fi AP interface itself.
+ *   - The default Main DNS server is typically the IP of the DHCP server itself.
  *   - This function can override it by setting server type ESP_NETIF_DNS_MAIN.
- *   - Other DNS Server types are not supported for the Wi-Fi AP interface.
+ *   - Other DNS Server types are not supported for the DHCP server.
+ *   - To propagate the DNS info to client, please stop the DHCP server before using this API.
  *
  * @param[in]  esp_netif Handle to esp-netif instance
  * @param[in]  type Type of DNS Server to set: ESP_NETIF_DNS_MAIN, ESP_NETIF_DNS_BACKUP, ESP_NETIF_DNS_FALLBACK

components/esp_wifi/include/esp_now.h

@@ -1,16 +1,8 @@
-// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2019-2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #ifndef __ESP_NOW_H__
 #define __ESP_NOW_H__
@@ -237,6 +229,20 @@ esp_err_t esp_now_del_peer(const uint8_t *peer_addr);
   */
 esp_err_t esp_now_mod_peer(const esp_now_peer_info_t *peer);
 
+/**
+  * @brief      Config ESPNOW rate of specified interface
+  *
+  * @attention  1. This API should be called after esp_wifi_start().
+  *
+  * @param      ifx  Interface to be configured.
+  * @param      rate Phy rate to be configured.
+  *
+  * @return
+  *    - ESP_OK: succeed
+  *    - others: failed
+  */
+esp_err_t esp_wifi_config_espnow_rate(wifi_interface_t ifx, wifi_phy_rate_t rate);
+
 /**
   * @brief     Get a peer whose MAC address matches peer_addr from peer list
   *

components/esp_wifi/include/esp_wifi.h

@@ -1210,20 +1210,6 @@ esp_err_t esp_wifi_ftm_resp_set_offset(int16_t offset_cm);
   */
 esp_err_t esp_wifi_config_11b_rate(wifi_interface_t ifx, bool disable);
 
-/**
-  * @brief      Config ESPNOW rate of specified interface
-  *
-  * @attention  1. This API should be called after esp_wifi_init() and before esp_wifi_start().
-  *
-  * @param      ifx  Interface to be configured.
-  * @param      rate Phy rate to be configured.
-  *
-  * @return
-  *    - ESP_OK: succeed
-  *    - others: failed
-  */
-esp_err_t esp_wifi_config_espnow_rate(wifi_interface_t ifx, wifi_phy_rate_t rate);
-
 /**
   * @brief      Set interval for station to wake up periodically at disconnected.
   *