**Backport:** https://codeberg.org/forgejo/forgejo/pulls/3046
This PR fixes an issue in the diff compare view, where when working on a fork that has not the same name as the upstream repo, the "View file" button links to a wrong, often missing, location.
Demonstration of this issue:
- Visit https://next.forgejo.org/mai-lapyst-test-org/upstream/compare/main...Mai-Lapyst/downstream:mai-lapyst-patch-1.
- Click the "View file" button of the patch.
- Get taken to `4fe947d522/README.md` (which does not exist and returns a 404) instead of `4fe947d522/README.md`. Note the different repository name (`upstream` vs `downstream`).
Co-authored-by: Mai-Lapyst <mai-lapyst@noreply.codeberg.org>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/3077
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>
Co-committed-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>