Fixes: https://github.com/go-gitea/gitea/issues/36152
Enable the `nilnil` linter while adding `//nolint` comments to existing
violations. This will ensure no new issues enter the code base while we
can fix existing issues gradually.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Since https://github.com/go-gitea/gitea/pull/25686, a few `interface{}`
have sneaked into the codebase. Add this replacement to `make fmt` to
prevent this from happening again.
Ideally a linter would do this, but I haven't found any suitable.