enforce nolint scope (#34851)

enable nolintlint scope requirement
add comments to new directives so it's more obvious why they are in
place

---

I can also toggle the mandatory comments on if that's something of
interest.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

services/gitdiff/gitdiff.go

@@ -1356,7 +1356,7 @@ func SyncUserSpecificDiff(ctx context.Context, userID int64, pull *issues_model.
 	// But as that does not work for all potential errors, we simply mark all files as unchanged and drop the error which always works, even if not as good as possible
 	if err != nil {
 		log.Error("Could not get changed files between %s and %s for pull request %d in repo with path %s. Assuming no changes. Error: %w", review.CommitSHA, latestCommit, pull.Index, gitRepo.Path, err)
-		err = nil //nolint
+		err = nil //nolint:ineffassign,wastedassign
 	}
 
 	filesChangedSinceLastDiff := make(map[string]pull_model.ViewedState)