Fix example code, add chapter to docs about interrupts and multicore issues

components/driver/include/driver/rmt.h

@@ -568,15 +568,14 @@ esp_err_t rmt_config(rmt_config_t* rmt_param);
  * @brief   register RMT interrupt handler, the handler is an ISR.
  *
  *          The handler will be attached to the same CPU core that this function is running on.
- *          @note
- *          If you already called rmt_driver_install to use system RMT driver,
+ * @note If you already called rmt_driver_install to use system RMT driver,
  *          please do not register ISR handler again.
  *
  * @param fn Interrupt handler function.
  * @param arg Parameter for handler function
  * @param  intr_alloc_flags Flags used to allocate the interrupt. One or multiple (ORred)
  *            ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.
- * @param  If non-zero, a handle to later clean up the ISR gets stored here.
+ * @param  handle If non-zero, a handle to later clean up the ISR gets stored here.
  *
  * @return
  *     - ESP_OK Success

components/driver/include/driver/uart.h

@@ -381,7 +381,8 @@ esp_err_t uart_isr_register(uart_port_t uart_num, void (*fn)(void*), void * arg,
 
 
 /**
- * @brief Free UART interrupt handler registered by uart_isr_register.
+ * @brief Free UART interrupt handler registered by uart_isr_register. Must be called on the same core as
+ * uart_isr_register was called.
  *
  * @param uart_num UART_NUM_0, UART_NUM_1 or UART_NUM_2
  *