change(doc): add notes for sleep current data tested in shieled box

docs/en/api-guides/low-power-mode/low-power-mode-wifi.rst

@@ -18,7 +18,7 @@ After the previous introduction to low power mode from a systemic perspective, t
 
   .. note::
 
-      All currents in the table are average currents, and the terms in the table are explained in the following text. Users can refer to them as needed.
+      All currents in the table are average currents, and the measured data are obtained by testing in a shielded box. The terms in the table are explained in the following text. Users can refer to them as needed.
 
 .. _Basic Principles of Wi-Fi Power Saving:
 

docs/zh_CN/api-guides/low-power-mode/low-power-mode-wifi.rst

@@ -19,7 +19,7 @@ Wi-Fi 场景下低功耗模式介绍
 
   .. note::
 
-      上表中所有电流均为平均电流，表中术语在下文均有介绍，用户可根据需求进行查看。
+      上表中所有电流均为平均电流，所测数据均在屏蔽箱中测试得出。表中术语在下文均有介绍，用户可根据需求进行查看。
 
 .. _Wi-Fi 省电的基本原理: