docs: fix typo in notification-center/client/react/multiple-tabs.mdx

Author: suravshrestha

notification-center/client/react/multiple-tabs.mdx

@@ -37,7 +37,7 @@ After specifying the `stores` prop, you can use the `storeId` property to in
 
 ### Managing feeds on the web UI
 
-1. How to add a new feed or select exisitng feed for In-App step?
+1. How to add a new feed or select existing feed for In-App step?
 
 To add a new feed, enable *Use Feeds* checkbox in In-App editor. Select from existing feeds or create a new feed by writing in the input field and then clicking on plus icon in the right side.
 
@@ -108,4 +108,4 @@ By specifying only a storeId, without a query, you could get all notifications.
     color="#0285c7"
     href="/api-reference/feeds/delete-feed"
   ></Card>
-</CardGroup>
+</CardGroup>