[Style Guide] Fix to Diagram page formatting (#27018)

Author: ToriLindsay

src/content/docs/style-guide/documentation-content-strategy/component-attributes/diagrams.mdx

@@ -33,13 +33,15 @@ We optimize SVG files with a [recurring script](https://github.com/cloudflare/cl
 
 ```md
 ![A simple flow diagram shows interactions between important elements of the design.](~/assets/images/firewall/simple-flow.png "An example flow diagram")
+```
+
 ## Mermaid diagrams
 
 Use Mermaid diagrams to illustrate product or process flows. If they work for your use case, Mermaid diagrams are preferable to other [diagrams](/style-guide/documentation-content-strategy/component-attributes/diagrams/) because they are more easily searchable and changeable.
 
 Our Mermaid diagrams are based on [`rehype-mermaid`](https://github.com/remcohaszing/rehype-mermaid/) and [`mermaid`](https://www.npmjs.com/package/mermaid).
 
-## Template
+### Template
 
 ```mermaid
 flowchart LR