Improve usability of path placeholder text

Problem / Motivation

If I start typing in the Add patches on the chosen project field, the URL placeholder text disappears. This creates cognitive load. It would be better if the placeholder text remained visible. I believe this is an emerging best practice for forms.

Steps:
1. Go to simplytest.me
2. In Project, type redirect
3. Choose redirect
4. Click Advanced options
5. Start typing in the field Add patches on the chosen project

Expected result: What was placeholder text reappears immediately below the field so it can still be seen.
Actual result: Placeholder text disappears and cannot be re-accessed without deleting the content.

If this is implemented with animation, as I have seen on some forms on other websites which do this, it needs to respect prefers-reduced-motion and not animate if that is set to reduce.

The code needs to have correct markup for screen readers.