Correcting grammatical errors in README file (#2880)

README.md

@@ -1827,7 +1827,7 @@ func main() {
 	quit := make(chan os.Signal)
 	// kill (no param) default send syscall.SIGTERM
 	// kill -2 is syscall.SIGINT
-	// kill -9 is syscall.SIGKILL but can't be catch, so don't need add it
+	// kill -9 is syscall.SIGKILL but can't be caught, so don't need to add it
 	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
 	<-quit
 	log.Println("Shutting down server...")