Use FetchCountable instead of Foldable

[NorfairKing]

Here's a way to support apis like this:

https://docs.github.com/en/rest/apps/installations?apiVersion=2022-11-28#list-repositories-accessible-to-the-user-access-token

I just realised it should also be possible to do this with a special Foldable type like this

data WithTotalCount (key :: Symbol) a = WithTotalCount { totalCount :: Int, values :: [a] } 

Up to you which you prefer.
If you don't want this patch then that's fine and I'll make such a foldable instead.

[NorfairKing]

Oh, looks like WithTotalCount already exists: https://hackage.haskell.org/package/github-0.29/docs/src/GitHub.Data.Actions.Common.html#WithTotalCount

Closing this.