title: Configuring the store with RTK-Query middleware
body: <p>I'm trying to add the RTK-Query middleware to a nested store structure,
  I'm getting a very long and non-descriptive typescript error when I add the api middleware...</p>
  <p>Here's my code:</p>
  <pre><code>export const rootReducer = combineReducers({
    foo: fooReducer,
    nested: combineReducers({
      bar: barReducer,
      [myFooApi.reducerPath]: myFooApi.reducer,  
    })
  });
  
  const store = configureStore({
    reducer: rootReducer,
    
    middleware: (getDefaultMiddleware) =&gt;   // Getting TS2322 error: type is not assignable to type...
      getDefaultMiddleware().concat(tokenListsApi.middleware)
  
  });
  
  </code></pre>
  <p>The error disappears when I move <code>[fooApi.reducerPath]</code> to the root of the reducer like so:</p>
  <pre><code>export const rootReducer = combineReducers({
    foo: fooReducer,
    bar: barReducer,
    [fooApi.reducerPath]: fooApi.reducer,  
  });
  </code></pre>
  <p>I was looking for examples of a nested usage of the RTK-Query Api reducer but couldn't find any... what am I missing?</p>