Greasy Fork镜像

Add repo/branch links to GitHub's "Comparing Changes" page

This adds a link to the fork's branch on the GitHub "Comparing changes" page (AKA the "Create a Pull Request" page). See https://stackoverflow.com/questions/77623282/how-do-i-get-my-remote-branch-url-from-the-github-create-pull-request-page for more details.