Compare across forks behavior is confusing

[jsoref]

🏷️ Discussion Type

Product Feedback

Body

For a url https://github.com/:owner/:repo/compare/:base...:head, there are currently two possible headings (there's no distinction in the url, which is unfortunate -- if you happen to be on Open a pull request and reload the page, you'll be sent to Comparing changes):

Comparing changes
Open a pull request

And there's one set of text:

Create a new pull request by comparing changes across two branches. If you need to, you can also compare across forks. Learn more about diff comparisons here.

Ideally it'd be easy to see from the prose if I am / am not able to compare across forks. The current text really doesn't make sense for the case where I already have the compare-across-forks drop downs:

It does make sense for the case where I am not able to compare across forks:

Currently, clicking compare across forks only changes those drop downs.

Ideally that prose would only be shown for the second case.

Instead, for the first case, the prose would be something like:

Create a new pull request by comparing changes across two branches. If you need to, you can change the base repository or switch to only work in this repository. Learn more about diff comparisons here.

[github-actions[bot]]

💬 Your Product Feedback Has Been Submitted 🎉

Thank you for taking the time to share your insights with us! Your feedback is invaluable as we build a better GitHub experience for all our users.

Here's what you can expect moving forward ⏩

• Your input will be carefully reviewed and cataloged by members of our product teams. 
  • Due to the high volume of submissions, we may not always be able to provide individual responses.
  • Rest assured, your feedback will help chart our course for product improvements.
• Other users may engage with your post, sharing their own perspectives or experiences. 
• GitHub staff may reach out for further clarification or insight. 
  • We may 'Answer' your discussion if there is a current solution, workaround, or roadmap/changelog post related to the feedback.

Where to look to see what's shipping 👀

• Read the Changelog for real-time updates on the latest GitHub features, enhancements, and calls for feedback.
• Explore our Product Roadmap, which details upcoming major releases and initiatives.

What you can do in the meantime 💻

• Upvote and comment on other user feedback Discussions that resonate with you.
• Add more information at any point! Useful details include: use cases, relevant labels, desired outcomes, and any accompanying screenshots.

As a member of the GitHub community, your participation is essential. While we can't promise that every suggestion will be implemented, we want to emphasize that your feedback is instrumental in guiding our decisions and priorities.

Thank you once again for your contribution to making GitHub even better! We're grateful for your ongoing support and collaboration in shaping the future of our platform. ⭐