Fix the wording for running the tests

Co-Authored-By: Deuchnord <[email protected]>

Author: alanpoulain

CONTRIBUTING.md

@@ -55,7 +55,7 @@ Be sure to add only **your modified files**. If another files are fixed by cs to
 
 When you send a PR, just make sure that:
 
-* You add valid test cases and run them (`yarn test`).
+* You add valid test cases (you can run them using `yarn test`).
 * Tests are green.
 * You make a PR on the related documentation in the [api-platform/doc](https://github.com/api-platform/doc) repository.
 * You make the PR on the same branch you based your changes on. If you see commits that you did not make in your PR, you're doing it wrong.