Properly implement Base.hash() for custom type

[anon60034542]

@fredrikekre

It would be great to add an example to make this clear then, do you want to contribute with that? Here is the docstring.

It’s funny you mention that, because I suggested it a few months ago .

I’m still learning so I don’t think that I’d be able to produce an accurate example. Perhaps someone with deep knowledge of Julia might update the documentation.