docs: Very minor grammar updates. (TanStack#2485)

Author: noccer

docs/src/pages/guides/caching.md

@@ -21,11 +21,11 @@ Let's assume we are using the default `cacheTime` of **5 minutes** and the defau
   - It will then cache the data using `'todos'` and `fetchTodos` as the unique identifiers for that cache.
   - The hook will mark itself as stale after the configured `staleTime` (defaults to `0`, or immediately).
 - A second instance of `useQuery('todos', fetchTodos)` mounts elsewhere.
-  - Because this exact data exist in the cache from the first instance of this query, that data is immediately returned from the cache.
+  - Because this exact data exists in the cache from the first instance of this query, that data is immediately returned from the cache.
 - A background refetch is triggered for both queries (but only one request), since a new instance appeared on screen.
   - Both instances are updated with the new data if the fetch is successful
 - Both instances of the `useQuery('todos', fetchTodos)` query are unmounted and no longer in use.
-  - Since there are no more active instances to this query, a cache timeout is set using `cacheTime` to delete and garbage collect the query (defaults to **5 minutes**).
+  - Since there are no more active instances of this query, a cache timeout is set using `cacheTime` to delete and garbage collect the query (defaults to **5 minutes**).
 - Before the cache timeout has completed another instance of `useQuery('todos', fetchTodos)` mounts. The query immediately returns the available cached value while the `fetchTodos` function is being run in the background to populate the query with a fresh value.
 - The final instance of `useQuery('todos', fetchTodos)` unmounts.
 - No more instances of `useQuery('todos', fetchTodos)` appear within **5 minutes**.