Fix typo in changelog

Fixed small typo in changelog file.

CHANGELOG

@@ -10,7 +10,7 @@ v 7.8.0 (unreleased)
   - View note image attachments in new tab when clicked instead of downloading them
   - Improve sorting logic in UI and API. Explicitly define what sorting method is used by default
   - Allow more variations for commit messages closing issues (Julien Bianchi and Hannes Rosenögger)
-  - Fix overflow at sidebar when have several itens
+  - Fix overflow at sidebar when have several items
   - Add notes for label changes in issue and merge requests
   - Show tags in commit view (Hannes Rosenögger)
   - Only count a user's vote once on a merge request or issue (Michael Clarke)