Update contributing.md

contributing.md

@@ -31,12 +31,12 @@ All submissions, including submissions by project members, require review. We
 use [GitHub pull requests](https://docs.github.com/articles/about-pull-requests)
 for this purpose.
 
-After creating a PR, a contributor needs to add `/gcbrun` to the comment to trigger CI
-for the PR, which includes the CloudBuild triggered e2e test `pr-review-trigger` 
-and `pr-review-trigger-ap-clusters` as shown below. 
+After creating a pull request, a collaborator needs to add `/gcbrun` as a comment
+to trigger CI for the PR, which includes the CloudBuild triggered e2e test
+`pr-review-trigger` and `pr-review-trigger-ap-clusters` as shown below. 
 ![image](https://github.com/user-attachments/assets/6a759456-e1dd-4a3b-95da-84c9f2b8b053)
 
-If any of the build fails, you can find the link to the build log for these triggers at
+If any of the builds fail, you can find the link to the build log for these triggers at
 the bottom of the details page by clicking `Details` link.