Add atomicModifyIORef_ and atomicModifyIORef'_

[chshersh]

Relude already offers lifted versions of atomicModifyIORef and atomicModifyIORef' functions. But these functions often used with () in the second place of tuple. See example in hintman:

• https://github.com/kowainik/hintman/blob/3dd38fa789098fbadfc905be801853942b81b7be/src/Hintman/Effect/TokenStorage.hs#L100-L101

The new functions were proposed to be added to base but they haven't landed:

• https://hackage.haskell.org/package/base-4.14.0.0/docs/Data-IORef.html#v:atomicModifyIORef
• Propose atomicModifyIORef_, atomicModifyIORef'_ ghc-proposals/ghc-proposals#230

I propose to implement them by ourselves. And if they ever going to be implemented in base, we can easily reexport them.

The type signatures:

atomicModifyIORef_  :: MonadIO m => IORef a -> (a -> a) -> m ()
atomicModifyIORef'_ :: MonadIO m => IORef a -> (a -> a) -> m ()