fix(docs): add guess_lang: false to pymdownx.highlight

Fixes NoneType error when code fences have no language specified.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mkdocs.yml

@@ -45,6 +45,7 @@ markdown_extensions:
       alternate_style: true
   - pymdownx.highlight:
       anchor_linenums: true
+      guess_lang: false
   - pymdownx.inlinehilite
   - pymdownx.snippets
   - tables