Fix golangci-lint revive warnings

Replace log.Printf with log.Print where no formatting is needed.

Author: paskal

backend/extractor/readability.go

@@ -187,7 +187,7 @@ func (f *UReadability) getContent(ctx context.Context, body, reqURL string, rule
 			log.Printf("[WARN] custom extractor failed for %s, error=%v", reqURL, err) // back to general parser
 		}
 	} else {
-		log.Printf("[DEBUG] no rules defined!")
+		log.Print("[DEBUG] no rules defined!")
 	}
 
 	return genParser(body, reqURL)

backend/main.go

@@ -63,7 +63,7 @@ func main() {
 		stop := make(chan os.Signal, 1)
 		signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
 		<-stop
-		log.Printf("[WARN] interrupt signal")
+		log.Print("[WARN] interrupt signal")
 		cancel()
 	}()