Fix grammer typo is CONTRIBUTING.md (#1041)

Author: ideen1

CONTRIBUTING.md

@@ -35,7 +35,7 @@ To send us a pull request, please:
 5. Send us a pull request, answering any default questions in the pull request interface.
 6. Pay attention to any automated CI failures reported in the pull request, and stay involved in the conversation.
 
-GitHub provides additional document on [forking a repository](https://help.github.com/articles/fork-a-repo/) and
+GitHub provides additional documentation on [forking a repository](https://help.github.com/articles/fork-a-repo/) and
 [creating a pull request](https://help.github.com/articles/creating-a-pull-request/).
 
 ## Project architecture