Update README.md

Author: flocked

README.md

@@ -169,9 +169,9 @@ An extended `NSCollectionViewDiffableDataSource that provides:
 
   ## OutlineViewDiffableDataSource
 
-  A diffable data source for NSOutlineView simliar to CollectionViewDiffableDataSource.
- 
- Example usage of a data source with a String as `ItemIdentifierType`:
+  A diffable data source for NSOutlineView.
+  
+  Example usage of a data source with a String as `ItemIdentifierType`:
 
  ```swift
     let dataSource = OutlineViewDiffableDataSource<String>(outlineView: outlineView, cellRegistration: cellRegistration)