Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -20,7 +20,7 @@ instructions for how to sign and return it. Once we receive it, we'll be able to
 accept your pull requests.
 
 ## Are you a Googler?
-If you are a Googler, plese make an attempt to submit an internal change rather than a GitHub Poll Request. 
+If you are a Googler, plese make an attempt to submit an internal change rather than a GitHub Pull Request. 
 If you are not able to submit an internal change a PR is acceptable as an alternative.