doc(gptimer): refactor doc structure

Split into two parts: quick start and advanced usage

Author: suda-morris

docs/en/api-reference/peripherals/etm.rst

@@ -68,7 +68,7 @@ Other Peripheral Events
 
     :SOC_SYSTIMER_SUPPORT_ETM: - You can call :cpp:func:`esp_systick_new_etm_alarm_event` to get the ETM event from RTOS Systick, one per CPU core.
     :SOC_SYSTIMER_SUPPORT_ETM: - Refer to :doc:`/api-reference/system/esp_timer` for how to get the ETM event handle from esp_timer.
-    :SOC_TIMER_SUPPORT_ETM: - Refer to :doc:`/api-reference/peripherals/gptimer` for how to get the ETM event handle from GPTimer.
+    :SOC_TIMER_SUPPORT_ETM: - Refer to :ref:`gptimer-etm-event-and-task` for how to get the ETM event handle from GPTimer.
     :SOC_GDMA_SUPPORT_ETM: - Refer to :doc:`/api-reference/system/async_memcpy` for how to get the ETM event handle from async memcpy.
     :SOC_MCPWM_SUPPORT_ETM: - Refer to :doc:`/api-reference/peripherals/mcpwm` for how to get the ETM event handle from MCPWM.
     :SOC_ANA_CMPR_SUPPORT_ETM: - Refer to :doc:`/api-reference/peripherals/ana_cmpr` for how to get the ETM event handle from analog comparator.
@@ -98,7 +98,7 @@ Other Peripheral Tasks
 
 .. list::
 
-    :SOC_TIMER_SUPPORT_ETM: - Refer to :doc:`GPTimer </api-reference/peripherals/gptimer>` for how to get the ETM task handle from GPTimer.
+    :SOC_TIMER_SUPPORT_ETM: - Refer to :ref:`gptimer-etm-event-and-task` for how to get the ETM task handle from GPTimer.
     :SOC_TEMPERATURE_SENSOR_SUPPORT_ETM: - Refer to :doc:`/api-reference/peripherals/temp_sensor` for how to get the ETM task handle from temperature sensor.
     :SOC_I2S_SUPPORTS_ETM:  - Refer to :doc:`/api-reference/peripherals/i2s` for how to get the ETM task handle from I2S.