feat(example): implement power management example for ESP chips

docs/en/api-reference/system/power_management.rst

@@ -130,6 +130,11 @@ These functions are particularly useful for:
 
 To enable profiling features (timing information for individual locks), enable the :ref:`CONFIG_PM_PROFILING` option in menuconfig.
 
+Application Example
+-------------------
+
+The :example:`lowpower/power_management` example demonstrates dynamic frequency scaling, automatic Light-sleep, and power management locks.
+
 Dynamic Frequency Scaling and Peripheral Drivers
 ------------------------------------------------
 

docs/zh_CN/api-reference/system/power_management.rst

@@ -130,6 +130,11 @@ ESP-IDF 使用预测性时间补偿机制来实现自动 Light-sleep。系统会
 
 要启用性能分析功能（单个锁的计时信息），请在 menuconfig 中启用 :ref:`CONFIG_PM_PROFILING` 选项。
 
+应用示例
+-------------------
+
+:example:`lowpower/power_management` 示例演示了动态调频、自动 Light-sleep 与电源管理锁。
+
 动态调频和外设驱动
 ------------------------------------------------