When ```plantuml header before @startuml is available, markdown PDF render it as code block

[bitandbytes]

Steps:
Markdown file code

```plantuml
@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: Another authentication Response
@enduml

Expectation:
Above code renders the sequence diagram

Actual behavior:
Above code render as code block.

Summary: The format of using ```plantuml is in complaint with the default markdown renderer that comes with VSCode. So if this is supported in makrdown-pdf it would be very convenient for users.

[peaz]

+1 for this issue. Would be useful to get support as the Markdown preview extension I use requires the ```plantuml code block