Mermaid codeblock does not render subgraphs

In a Capacities Mermaid code block, the following example from the Mermaid documentation does not render as expected:
```mermaid
erDiagram

direction LR

subgraph title1

A1 ||--|| A2 : links

end

subgraph title2

B1 ||--|| B2 : links

end

subgraph title3

C1 ||--|| C2 : links

end

title1 ||--|| title2 : links

title2 ||--|| title3 : links

title2 ||--|| C2 : links

```
The diagram syntax is documented here: https://mermaid.js.org/syntax/entityRelationshipDiagram.html#relationships-involving-subgraphs

Please clarify whether this syntax is supported in Capacities, or investigate why the diagram does not render.

Mermaid.js screengrab

Capacities.io screengrab

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