feat: Mark syntax blocks - #24

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v3, maxim-lobanov/setup-xcode@60606e260d2fc5762a71e64e74b2174e8ea3c8bd. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/