Description

I found errors in the Flowchart documentation in the production and latest develop branch.

I previously reported a similar issue (#6455) about failing previews in the Flowchart documentation, which was fixed. However, I found two new documentation preview errors that are different from the previous issue:

1. The Image Shape example code fails to render because the sample image URL (https://example.com/image.png) is not accessible
   • This error is occurring in production as well
2. The Markdown Strings example has a syntax error

These issues are in different sections of the documentation and have various causes from the previous issue.

Steps to reproduce

1. Checkout the develop branch and start a local server for docs
2. Open the Flowchart documentation page (http://localhost:3333/syntax/flowchart.html)
3. Check the Image Shape section - the preview is not rendered
4. Check the Markdown Strings section - the preview is not rendered
5. Scroll to the bottom of the page - you will see "Syntax error in text mermaid version 11.6.0" displayed

Screenshots

The following screenshot shows the docs for the latest develop branch.

Code Sample

Setup

• Mermaid version: 11.6.0
• Browser and Version: [Chrome 136, Safari 18.4, Firefox 137]

Suggested Solutions

1. For the Image Shape example:
   • Remove the preview since the sample image URL is not accessible

     -```mermaid-example
     +```
     flowchart TD
         A@{ img: "https://example.com/image.png", label: "Image Label", pos: "t", w: 60, h: 60, constraint: "off" }

   • https://github.com/mermaid-js/mermaid/blob/develop/packages/mermaid/src/docs/syntax/flowchart.md?plain=1#L579-L582
2. For the Markdown Strings example:
   • Fix the syntax error in the example code

     +---
     config:
       flowchart:
         htmlLabels: false
     ---
     flowchart LR
     subgraph "One"
       a("`The **cat**
       in the hat`") -- "edge label" --> b{{"`The **dog** in the hog`"}}
     end
     subgraph "`**Two**`"
       c("`The **cat**
       in the hat`") -- "`Bold **edge label**`" --> d("The dog in the hog")
     end

   • https://github.com/mermaid-js/mermaid/blob/develop/docs/syntax/flowchart.md?plain=1#L1602-L1616
   • https://github.com/mermaid-js/mermaid/blob/develop/packages/mermaid/src/docs/syntax/flowchart.md?plain=1#L982-L996

Additional Context

I'm prepared to create a Pull Request to fix these issues.