periph/uart: fix line length in doc header

drivers/include/periph/uart.h

@@ -12,27 +12,30 @@
  * @brief       Low-level UART peripheral driver
  *
  * This is a basic UART (Universal Asynchronous Receiver Transmitter) interface
- * to allow platform independent access to the MCU's serial communication abilities.
- * This interface is intentionally designed to be as simple as possible, to allow
- * for easy implementation and maximum portability. In RIOT we only use the
- * common 8-N-1 format of the serial port (8 data bits, no parity bit, one stop bit).
- *
- * The simple interface provides capabilities to initialize the serial communication
- * module, which automatically enables for receiving data, as well as writing data
- * to the UART port, which means transmitting data. The UART device and the
- * corresponding pins need to be mapped in `RIOT/boards/ * /include/periph_conf.h`.
- * Furthermore you need to select the baudrate for initialization which is typically
- * {9600, 19200, 38400, 57600, 115200} baud. Additionally you should register a
- * callback function that is executed in interrupt context when data is being received.
- * The driver will then read the received data byte, call the registered callback
- * function and pass the received data to it via its argument. The interface enforces
- * the receiving to be implemented in an interrupt driven mode. Thus, you never know how
- * many bytes are going to be received and might want to handle that in your specific
- * callback function. The transmit function can be implemented in any way.
- *
- * By default the @p UART_DEV(0) device of each board is initialized and mapped to STDIO
- * in RIOT which is used for standard input/output functions like `printf()` or
- * `puts()`.
+ * to allow platform independent access to the MCU's serial communication
+ * abilities. This interface is intentionally designed to be as simple as
+ * possible, to allow for easy implementation and maximum portability. In RIOT
+ * we only use the common 8-N-1 format of the serial port (8 data bits, no
+ * parity bit, one stop bit).
+ *
+ * The simple interface provides capabilities to initialize the serial
+ * communication module, which automatically enables for receiving data, as well
+ * as writing data to the UART port, which means transmitting data. The UART
+ * device and the corresponding pins need to be mapped in
+ * `RIOT/boards/ * /include/periph_conf.h`. Furthermore you need to select the
+ * baudrate for initialization which is typically {9600, 19200, 38400, 57600,
+ * 115200} baud. Additionally you should register a callback function that is
+ * executed in interrupt context when data is being received. The driver will
+ * then read the received data byte, call the registered callback function and
+ * pass the received data to it via its argument. The interface enforces the
+ * receiving to be implemented in an interrupt driven mode. Thus, you never know
+ * how many bytes are going to be received and might want to handle that in your
+ * specific callback function. The transmit function can be implemented in any
+ * way.
+ *
+ * By default the @p UART_DEV(0) device of each board is initialized and mapped
+ * to STDIO in RIOT which is used for standard input/output functions like
+ * `printf()` or `puts()`.
  *
  * @{
  *