fix: construtors -> constructors

op-service/metrics/ref_metrics.go

@@ -34,7 +34,7 @@ type RefMetrics struct {
 var _ RefMetricer = (*RefMetrics)(nil)
 
 // MakeRefMetrics returns a new RefMetrics, initializing its prometheus fields
-// using factory. It is supposed to be used inside the construtors of metrics
+// using factory. It is supposed to be used inside the constructors of metrics
 // structs for any op service after the full namespace and factory have been
 // setup.
 //