Merge branch 'feature/add_esp_rom_printf_to_api_reference' into 'master'

docs: Add esp_rom_printf to API Reference

Closes DOC-454

See merge request espressif/esp-idf!10251

docs/Doxyfile

@@ -259,6 +259,7 @@ INPUT = \
     $(IDF_PATH)/components/esp_system/include/esp_async_memcpy.h \
     ## Logging
     $(IDF_PATH)/components/log/include/esp_log.h \
+    $(IDF_PATH)/components/esp_rom/include/esp_rom_sys.h \
     ## Base MAC address
     ## NOTE: for line below header_file.inc is not used
     $(IDF_PATH)/components/esp_system/include/esp_system.h \

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

@@ -30,6 +30,7 @@ System API
     Sleep Modes <sleep_modes>
     Watchdogs <wdts>
     System Time <system_time>
+    Internal and Unstable API <internal-unstable>
 
 
 Code examples for this API section are provided in the :example:`system` directory of ESP-IDF examples.

docs/en/api-reference/system/internal-unstable.rst

@@ -0,0 +1,10 @@
+Internal and Unstable APIs
+==========================
+
+This section is listing some APIs that are internal or likely to be changed or removed in the next releases of ESP-IDF.
+
+
+API Reference
+-------------
+
+.. include-build-file:: inc/esp_rom_sys.inc

docs/zh_CN/api-reference/system/internal-unstable.rst

@@ -0,0 +1 @@
+.. include:: ../../../en/api-reference/system/internal-unstable.rst