add update type

[hoilzz]

To specify SetCountContextType, it is written as immerHook<S>[1].

So, I suggest Update type.

const CountContext = React.createContext(0);

type SetCountContextType = ImmerHook<number>[1];
// type SetCountContextType = Update<number>;

const SetCountContext = React.createContext<SetCountContextType>(
  {} as SetCountContextType
);

export default function App() {
  const [count, produceCount] = useImmer(0);

  return (
    <CountContext.Provider value={count}>
      <SetCountContext.Provider value={produceCount}>
		{...}
      </SetCountContext.Provider>
    </CountContext.Provider>
  );
}

[deluksic]

Do you think it makes sense to call this Produce<> instead of Update<> ?

[mweststrate]

Looking fine, thanks!