fixed error in persist example and added typescript (#2978)

* fixed error in persist example and added typescript

* chore: formatted code

---------

Co-authored-by: sidahmedabdelillah <[email protected]>

Author: sidahmedabdelillah

docs/integrations/persisting-store-data.md

@@ -21,7 +21,32 @@ for more details.
 import { create } from 'zustand'
 import { persist, createJSONStorage } from 'zustand/middleware'
 
-export const useBearStore = create(
+export const useBearStore = create()(
+  persist(
+    (set, get) => ({
+      bears: 0,
+      addABear: () => set({ bears: get().bears + 1 }),
+    }),
+    {
+      name: 'food-storage', // name of the item in the storage (must be unique)
+      storage: createJSONStorage(() => sessionStorage), // (optional) by default, 'localStorage' is used
+    },
+  ),
+)
+```
+
+## Typescript simple example
+
+```ts
+import { create } from 'zustand'
+import { persist, createJSONStorage } from 'zustand/middleware'
+
+type BearStore = {
+  bears: number
+  addBear: () => void
+}
+
+export const useBearStore = create<BearStore>()(
   persist(
     (set, get) => ({
       bears: 0,