Fix migration guide

Signed-off-by: Armin Mehinovic <4390250+arminmeh@users.noreply.github.com>

docs/data/migration/migration-data-grid-v7/migration-data-grid-v7.md

@@ -73,7 +73,7 @@ Below are described the steps you need to make to migrate from v7 to v8.
 
 - Return type of the `useGridApiRef()` hook and the type of `apiRef` prop are updated to explicitly include the possibilty of `null`. In addition to this, `useGridApiRef()` returns a reference that is initialized with `null` instead of `{}`.
 
-  Only the initial value and the type are updated. Logic that initializes the API and its availability remained the same, which means that if you could access API in a particular line of your code before you will be able to access it as well after this change.
+  Only the initial value and the type are updated. Logic that initializes the API and its availability remained the same, which means that if you could access API in a particular line of your code before, you are able to access it as well after this change.
 
   Depending on the context in which the API is being used, you can decide what is the best way to deal with `null` value. Some options are: