This commit changes the commit link rendering (link to a single commit,
a diff, a PR, etc):
1. If it is a link to something on the local instance:
1.1. If it is to the same org and repo, the link is just e.g. the
commit hash
1.2. If it is to another repo, the link is the org/repo/commit hash
2. If the link is to another instance:
The link is the domain/optional sub path/org/repo/commit hash
This change is made to keep the link as short as possible, while not
hiding that the link may go to an external instance.
Followup to !9146Closes#10241
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/10530
Reviewed-by: Gusted <gusted@noreply.codeberg.org>