docs: Generate Doxygen directives for API documentation

This is to resolve issue reported in https://github.com/espressif/esp-idf/issues/130.

docs/api-reference/system/ota.rst

@@ -2,7 +2,7 @@ Over The Air Updates (OTA)
 ==========================
 
 OTA Process Overview
-^^^^^^^^^^^^^^^^^^^^
+--------------------
 
 The OTA update mechanism allows a device to update itself based on data received while the normal firmware is running
 (for example, over WiFi or Bluetooth.)
@@ -17,7 +17,7 @@ next boot.
 .. _ota_data_partition:
 
 OTA Data Partition
-^^^^^^^^^^^^^^^^^^
+------------------
 
 An OTA data partition (type ``data``, subtype ``ota``) must be included in the :doc:`Partition Table <../../api-guides/partition-tables>`
 of any project which uses the OTA functions.
@@ -46,32 +46,7 @@ End-to-end example of OTA firmware update workflow: :example:`system/ota`.
 API Reference
 -------------
 
-Header Files
-^^^^^^^^^^^^
+.. include:: /_build/inc/esp_ota_ops.inc
 
-  * :component_file:`app_update/include/esp_ota_ops.h`
 
-Macros
-^^^^^^
 
-.. doxygendefine:: ESP_ERR_OTA_BASE
-.. doxygendefine:: ESP_ERR_OTA_PARTITION_CONFLICT
-.. doxygendefine:: ESP_ERR_OTA_SELECT_INFO_INVALID
-.. doxygendefine:: ESP_ERR_OTA_VALIDATE_FAILED
-.. doxygendefine:: OTA_SIZE_UNKNOWN
-
-Type Definitions
-^^^^^^^^^^^^^^^^
-
-.. doxygentypedef:: esp_ota_handle_t
-
-Functions
-^^^^^^^^^
-
-.. doxygenfunction:: esp_ota_begin
-.. doxygenfunction:: esp_ota_write
-.. doxygenfunction:: esp_ota_end
-.. doxygenfunction:: esp_ota_get_running_partition
-.. doxygenfunction:: esp_ota_set_boot_partition
-.. doxygenfunction:: esp_ota_get_boot_partition
-.. doxygenfunction:: esp_ota_get_next_update_partition