Fix type of render in refactor-1.md

[slowdive-]

The first refactoring exercise mentions to change the render function to :: RenderState -> Builder to use Builder instead of String. Unless I'm missing something this should be :: BoardInfo -> RenderState -> Builder, since the String version also uses the BoardInfo. This might be potentially confusing.

Edit: + Fix more type signatures in refactor-4.md

[lsmor]

Thanks for the contribution. Would you mind to merge from main to main? This project's git tree looks something like

----- main ---------> changes in docs ---->
  |-----> solution-mvp
     |---> snake-fury-exercise
     |---> solution-refactor-1
        |---> solution-refactor-2.1
           |---> solution-refactor-2.2
              |---> etc...

I know is a mess and I should change it, but it is the way it worked for me during the building of the challenge. When I change some documentation I can merge main in every other branch.

[slowdive-]

Sure! I also squashed the commits. Seems like I can't edit my own branch in the PR though, but my main and snake-fury-exercise point to the same commit, so it should be correct the way the PR is setup now?

[slowdive-]

Thanks for merging and thanks for providing this exercise, you've clearly put a lot of work into this :)

[lsmor]

Thank you for PR!! There are many small mistakes I am not aware of :). Also if you will, provide some feedback to keep improving the challenge

[slowdive-]

Yes, I wasn't sure where to provide feedback so I'll just comment here.

Exercise 4 was the first one that was new territory for me, so naturally it took me a long time to figure some of it out. One thing I was missing that would have helped me, was the solution for implementing Functor, Applicative, etc. manually for the newtype. The solution branch uses GeneralizedNewtypeDeriving to just derive them. Maybe it would be helpful if one of the files, e.g. GameState.hs, kept the manual implementations of the type classes?