[chore] Add in Reference URL for docker featuregate (#16515)

Adding featuregate reference for docker

receiver/dockerstatsreceiver/factory.go

@@ -37,6 +37,7 @@ func init() {
 		useScraperV2ID,
 		featuregate.StageBeta,
 		featuregate.WithRegisterDescription("When enabled, the receiver will use the function ScrapeV2 to collect metrics. This allows each metric to be turned off/on via config. The new metrics are slightly different to the legacy implementation."),
+		featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/9794"),
 	)
 }