close Markdown inline code, "`" was forgotten in docs

### Change Type

Cleanup (formatting, typos, etc.)

### Area

Configuration

### Proposed Changes

See

```Markdown
`https://).
```

in https://netboxlabs.com/docs/netbox/configuration/security/#csrf_trusted_origins

Once accepted, feel free to assign me, ~~reopen #20712~~, merge it and close the issue as solved. Job done :)