fix: address verified review findings (labels-milestones-time-1)

Signed-off-by: bircni <bircni@icloud.com>

internal/services/errors.go

@@ -120,6 +120,8 @@ func (e *ConflictError) Unwrap() error { return e.Err }
 type AmbiguousError struct {
 	Kind, Key, Scope string
 	IDs              []int64
+	// Hint replaces the advice to pass an ID where IDs do not select the resource.
+	Hint string
 }
 
 func (e *AmbiguousError) Error() string {
@@ -131,7 +133,7 @@ func (e *AmbiguousError) Error() string {
 	if e.Scope != "" {
 		text += " in " + e.Scope
 	}
-	return text + " (IDs " + strings.Join(ids, ", ") + "); pass an ID"
+	return text + " (IDs " + strings.Join(ids, ", ") + "); " + cmp.Or(e.Hint, "pass an ID")
 }
 
 // refusals maps the messages Gitea gives for refused requests onto conflict reasons. Each entry