Enable fenced code parsing

Add pymdownx.superfences markdown extension so fenced code blocks render with language metadata instead of showing language tokens in content.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: MariusStorhaug

.github/zensical.toml

@@ -69,6 +69,8 @@ permalink = true
 
 [project.markdown_extensions.pymdownx.details]
 
+[project.markdown_extensions.pymdownx.superfences]
+
 [project.extra.consent]
 title = "Cookie consent"
 description = """