Update title of Arduino Uno pin names dev guide

Author: Marcelo Salazar

docs/porting/standard_pin_names/pin_names_dev_guide_arduino.md

@@ -1,4 +1,4 @@
-## Arduino Uno 
+## Arduino Uno Pin Names
 
 The Arduino Uno connector is a standardised connector in Mbed, which has a set amount of exposed functionality. To achieve meaningful portability of application code across various Mbed boards that are Arduino Uno compliant, the pin names used for the connector pins are common across these boards.
 
@@ -62,4 +62,4 @@ For more details about UART, please check the Mbed API.
 
 **PWM/Timer pins**    
 
-In the Arduino Uno standard, there are only 6 PWM and timers available on pins ARDUINO_UNO_D3, ARDUINO_UNO_D5, ARDUINO_UNO_D6, ARDUINO_UNO_D9, ARDUINO_UNO_D10 and ARDUINO_UNO_D11. However, Mbed boards may support the usage of PWM and timers functions on other pins as well.
+In the Arduino Uno standard, there are only 6 PWM and timers available on pins ARDUINO_UNO_D3, ARDUINO_UNO_D5, ARDUINO_UNO_D6, ARDUINO_UNO_D9, ARDUINO_UNO_D10 and ARDUINO_UNO_D11. However, Mbed boards may support the usage of PWM and timers functions on other pins as well.