docs: update to front-matter config

Author: rjaegers

docs/templates/requirements.md.j2

@@ -1,7 +1,8 @@
 ---
 title: "Requirements specification for amp-devcontainer"
-author: [Ron Jaegers]
-date: "25-Sept-2025"
+author: ["@rjaegers"]
+block-headings: 4
+date: "Sept-2025"
 keywords: [Requirements, amp-devcontainer]
 lang: "en"
 titlepage: true