docs: secret removal examples

cli/app/secret.go

@@ -148,6 +148,11 @@ var AppSecretInsertCommand = &cobra.Command{
 This can be useful when you want to manually generate secrets for an app
 environment. Typically, you can let Abra generate them for you on app creation
 (see "abra app new --secrets/-S" for more).`,
+	Example: `  # insert regular secret
+  abra app secret insert 1312.net my_secret v1 mySuperSecret
+
+  # insert secret as file
+  abra app secret insert 1312.net my_secret v1 secret.txt -f`,
 	Args: cobra.MinimumNArgs(4),
 	ValidArgsFunction: func(
 		cmd *cobra.Command,