### Bug description

`subtitle: ...` is ignored if the title is not present. YAML:

```yaml
subtitle: Subtitle
jupyter: python3
```
Output

![image](https://user-images.githubusercontent.com/12725868/224477894-d3761ff4-c2cd-4eea-9c72-198a33e863dd.png)

The issue is not present with the following YAML:

```yaml
---  
title: Project
subtitle: Subtitle
jupyter: python3
---
```

Then output:
![image](https://user-images.githubusercontent.com/12725868/224478329-1f80e321-2eed-432f-8412-0717fe814279.png)


I use Windows 10, VS Code and 
![image](https://user-images.githubusercontent.com/12725868/224478189-3b80b240-e1d4-4dd6-a93b-e675300e312c.png)

# Expected behavior

1) Either fix the issue (show the toolbar) in both situations
2) Or produce a **clear** warning that some setup options are ignored and provide an example of how to get the desired outcome.


### Checklist

- [X] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [X] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [X] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] Please document the operating system you're running. If on Linux, please provide the specific distribution.
dragonstyle
2023-03-11T10:07:47Z
GegznaV
bug
closed
`subtitle: ...` is silently ignored if title is not present
https://github.com/quarto-dev/quarto-cli/issues/4764