Wolfram Documentation on Mathematica is excellent in my humble opinion. Here is a function I use very often, convolve.
https://reference.wolfram.com/language/ref/Convolve.html
Notice how the interface is very well described, there are examples on how to use it, but there are no implementation details.
That's not an "easier to keep documentation up to date" type of thing ;), but is definitely an example of good documentation.
Unlike the Apple approach mentioned above. :( :( :(
Wolfram Documentation on Mathematica is excellent in my humble opinion. Here is a function I use very often, convolve.
https://reference.wolfram.com/language/ref/Convolve.html
Notice how the interface is very well described, there are examples on how to use it, but there are no implementation details.