Add Font Awesome CSS for proper icons in admonition boxes

Author: ccarouge

documentation/mkdocs.yml

@@ -136,6 +136,7 @@ extra:
 
 extra_css:
   - "https://fonts.googleapis.com/icon?family=Material+Icons"   # Material Icons Reference - https://material.io/resources/icons/?style=baseline
+  - "https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.0/css/all.min.css"
   - fontello/css/fontello-codes.css
   - fontello/css/fontello-ie7-codes.css
   - fontello/css/fontello-ie7.css