Fix the PullReview tool link

CONTRIBUTING.md

@@ -113,4 +113,4 @@ For examples of feedback on merge requests please look at already [closed merge
 1.  [Shell commands](doc/development/shell_commands.md) created by GitLab contributors to enhance security
 1.  [Markdown](http://www.cirosantilli.com/markdown-styleguide)
 
-This is also the style used by linting tools such as [Rubocop](https://github.com/bbatsov/rubocop), PullReview[https://www.pullreview.com/] and [Hound CI](https://houndci.com).
+This is also the style used by linting tools such as [Rubocop](https://github.com/bbatsov/rubocop), [PullReview](https://www.pullreview.com/) and [Hound CI](https://houndci.com).