Syntax Highlight Transform

SyntaxHighlightTransform normalizes fenced-code language tags.

What changes

• strips surrounding whitespace from the language tag
• lowercases the language tag
• leaves the code body untouched

Example

```Rust      -> ```rust
```  Python  -> ```python
```JavaScript -> ```javascript

Why it matters

Consistent language tags improve downstream syntax highlighting behavior in Pandoc-generated output.