alerts do not render correctly in graphite comments example markdown

> [!NOTE]
> Heavy CI skipped by optimize-ci (docs-only or Graphite optimization).

screnshot left: graphite // right: github

(If applicable) To help us repro, please send the following if you haven't already: - PR links, screenshots, and/or debug output if applicable - Repro steps - Does this happen consistently? Just to you or others on your team also? - Is this a regression? Is the problem new? - If you're having an issue with the CLI, please send us debug logs using

gt feedback --with-debug-context <any message>