There is an issue with the way the mermaid language file support was added. Markdown files are processing/highlighting any mermaid lines in fenced blocks as mermaid instead of mermaid-defined fenced code blocks.
Reproduce:
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graph LR
A --> B
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```mermaid
graph LR
A --> B
This appears to be an issue with the fact that `mermaid` was added as an include at the top of the language file in the `patterns` section. It was added for mermaid files, but means that the markdown begin/end block checking is being skipped for markdown code blocks.
There is an issue with the way the mermaid language file support was added. Markdown files are processing/highlighting any mermaid lines in fenced blocks as mermaid instead of mermaid-defined fenced code blocks.
Reproduce:
graph LR A --> B