fix descriptions

README.md

@@ -1,7 +1,7 @@
 Expiration check
 ================
 
-Checks the expiration dates of domains et certificates.
+Checks the expiration dates of domains and certificates.
 
 Domain expiration check uses [`RDAP`](https://about.rdap.org/) and fallback with a `whois` request.
 

app.go

@@ -36,6 +36,8 @@ func App() *cli.App {
 	}
 
 	return &cli.App{
+		Usage:    "Checks the expiration dates of domains and certificates",
+		HelpName: "expiration-check",
 		Commands: []*cli.Command{
 			{
 				Name:    "certificate",