Added the description of the behavior of getValue on option elements
Added the description of the behavior of getValue on option elements

NodeElement::selectOption is expecting this behavior, which is indeed
necessary as the value of an option does not only depend on the value
attribute.

aik099/Mink,Chekote/Mink,minkphp/Mink,jordi12100/Mink,jhedstrom/Mink,Chekote/Mink,talib570/Mink,talib570/Mink,jordi12100/Mink,minkphp/Mink,jhedstrom/Mink,Behat/Mink