Yarn already implies where it comes from

Signed-off-by: Shin'ya Minazuki <shinyoukai@laidback.moe>

cmd/login.go

@@ -20,7 +20,7 @@ var (
 
 var loginCmd = &cobra.Command{
 	Use: "login",
-	Short: "Authenticate against a Yarn.social pod",
+	Short: "Authenticate against a Yarn pod",
 	Aliases: []string{"auth", "signin"},
 	Args: cobra.MaximumNArgs(0),
 	Run: func(_ *cobra.Command, _ []string) {