ESP32-C2 has a single group timer, thus it will use it for the interrupt watchdog, which is more critical than the task watchdog. The latter is implement in software thanks to the `esp_timer`component.
This commit tidys the INT WDT code formatting, comments, and API descriptions.
This commit makes the interrupt WDT API private. To use the API, IDF components should now '#include "esp_private/esp_int_wdt.h"'