Incorrect Documentation for ARM template

According to the [documentation](https://learn.microsoft.com/en-us/azure/virtual-machines/extensions/custom-script-linux#template-deployment) this is a valid template:

```json
{
"name": "config-app",
"type": "Extensions",
"location": "[resourceGroup().location]",
"apiVersion": "2019-03-01",
"dependsOn": [
"[concat('Microsoft.Compute/virtualMachines/', concat(variables('vmName'),copyindex()))]"
],
"tags": {
"displayName": "config-app"
},
"properties": {
"publisher": "Microsoft.Azure.Extensions",
"type": "CustomScript",
"typeHandlerVersion": "2.1",
"autoUpgradeMinorVersion": true,
"settings": {
"skipDos2Unix":false,
"timestamp":123456789
},
"protectedSettings": {
"commandToExecute": "",
"script": "",
"storageAccountName": "",
"storageAccountKey": "",
"fileUris": ["https://.."],
"managedIdentity" : ""
}
}
}
```

Unfortunately it is not since the `"type": "Extensions",` is invalid as this error is showed when try to deploy: _the property type is invalid_ for this template resource.