Use `EffectFnX` functions internally

[hdgarrood]

To prevent issues like #27 from occurring again.

[paf31]

👍

[artemisSystem]

From what i can tell, this issue is about using (what's now called) Effect.Uncurried (EffectFnX) instead of FnX and mkEffect. The use of mkEffect prevents things like #27 by my understanding, but it's still an old and convoluted way of doing things. Perhaps we could switch over to EffectFnX at the same time as changes for #19 are made.

[JordanMartinez]

I was thinking the same thing when I reviewed your other PR. We should be using EffectFnX now.

[hdgarrood]

My intention when I created this was only to change the implementations internally, not to change the type signatures of any exported functions - I don't think we should use EffectFn in the exported functions in this library.

[artemisSystem]

Agreed