feat(docs): use github-flavored markdown at the shuttle level too

docs/doc_header.md.mustache

@@ -4,17 +4,25 @@ title: |
     {{name}} Datasheet
 subtitle: Project Repository [{{repo}}]({{repo}})
 documentclass: scrartcl
-date: \today{}
+date: |
+  ```{=latex}
+  \today{}
+  ```
 geometry: "left=2cm,right=2cm,top=2cm,bottom=2.5cm"
 fontsize: 14pt
 mainfont: Latin Modern Sans
 header-includes:
-- \usepackage{hyperref}
-- \hypersetup{colorlinks=true,
+- |
+  ```{=latex}
+  \usepackage{hyperref}
+  \hypersetup{colorlinks=true,
           urlcolor=blue,
           linkcolor=[rgb]{0,0,0.5},
           allbordercolors={0 0 0},
           pdfborderstyle={/S/U/W 1} }
+  ```
 ---
 
+```{=latex}
 \pagebreak
+```