Currently, if a Pull Request is updated with a new commit that results in a new diff, a notification is shown to a PR reviewer currently looking at the PR, but only if they are on a tab other than Overview (e.g. "Diff"). If they happen to be on the Overview tab when the PR diff changes, no notification is shown, and if they subsequently approve the PR, they would approve these unseen changes that they were not notified about.

This should be changed so that the notification is displayed regardless of which tab they're on.