Mark a parameter as optional (or has a default) with YARD

YARD now supports param defaults automatically.

YARD automatically figures out the default value based on the method definition. Sweedish!

For example, the following code documentation will produce the subsequent YARD doc:

Code Documentation

# Squares a number.
# 
# @param number [Integer] The number to square.
#
def square_a_number(number = 2)
  number * number
end

Resulting YARD Documentation

Parameters:
  number (Integer optional) (defaults to: 2)