fix grammar, sentence should read: '[..] every time the commit is cherry-picked and/or pushed to a fork'

Author: davidmrdavid

llvm/docs/DeveloperPolicy.rst

@@ -415,7 +415,7 @@ Below are some guidelines about the format of the message itself:
 
 * Avoid 'tagging' someone's username in your commits and PR descriptions
   (e.g., `@<someUser>`), doing so results in that account receiving a notification
-  every time the commit is cherry-picked and to a fork.
+  every time the commit is cherry-picked and/or pushed to a fork.
 
 LLVM uses a squash workflow for pull requests, so as the pull request evolves
 during review, it's important to update the pull request description over the