Remove a dead link to the PR header

Author: dunglas

Diff for: .github/CONTRIBUTING.md

@@ -2,6 +2,4 @@ Contributing
 ------------
 
 We love contributors! For more information on how you can contribute to the
-Symfony documentation, please read [Contributing to the Documentation](https://symfony.com/doc/current/contributing/documentation/overview.html)
-and notice the [Pull Request Format](https://symfony.com/doc/current/contributing/documentation/overview.html#pull-request-format)
-that helps us merge your pull requests faster!
+Symfony documentation, please read [Contributing to the Documentation](https://symfony.com/doc/current/contributing/documentation/overview.html).