pub fn markdown_code_language(lang: Option<&str>) -> Option<&str>Expand description
#VAPP-258 (fixtures/markdown-render.json): the language a Markdown
fence’s info string (```ts) is highlighted in: a catalog language
other than plain and ansi (whose escapes the tokenizer drops), else
None = plain text, no colours (src/code.ts markdownCodeLanguage).