Diagrams beginning with --- are not valid

[tekumara]

```mermaid
----
config:
  look: handDrawn
----
graph TD
  B[Text] --> C{Decision}
  C -->|One| D[Result 1]
  C -->|Two| E[Result 2]
```

Will error with

Error: Diagrams beginning with --- are not valid. If you were trying to use a YAML front-matter, please ensure that you've correctly opened and closed the YAML front-matter with un-indented --- blocks

[tekumara]

Instead use:

```mermaid { look: 'handDrawn' }
graph TD
  B[Text] --> C{Decision}
  C -->|One| D[Result 1]
  C -->|Two| E[Result 2]
```