Remove `taggedSum`?

[m-bock]

As discussed in #70 there are considerations to remove taggedSum.

I think the question is how backwards compatible the library wants to be.

Maybe a deprecation would be a bit milder.

[garyb]

I guess it's harmless enough to keep in here, perhaps we just update the comment pointing out that there are other options with better ergonomics now. I'll probably just go ahead and drop it from purescript-codec-json when doing updates over there though.

[wclr]

I would move them to a different module (taggedSum, enumSum) as something meant for specific cases or legacy.

[garyb]

I'm happy with them where they are, they are still for dealing with sum types.

[wclr]

Well, enumSum is actually a String based prismaticCodec. Custom taggedSum codec is easy to construct manually just with codec' and record, it will not require much more code and will give more flexibility if needed.

So think those two better be removed form Codec.JSON especitally if tag mapping with something like described here will be supported.