docs(mkdocs): Fix font

The font was actually loaded from Google Fonts, not locally.
The theme.font.text property in mkdocs.yaml can only reference
Google Fonts, which we can disable completely and rely on
loading the proper font from CSS. Unfortunately the way it was
defined before didn't work, see the mkdocs documentation:
https://squidfunk.github.io/mkdocs-material/setup/changing-the-fonts/#docsstylesheetsextracss

Author: kissgyorgy

docs/extra.css

@@ -3,8 +3,8 @@
     src: url("ArtegraSans-Regular.ttf");
 }
 
-html {
-    font-family: "Artegra Sans", Sans-serif;
+:root {
+    --md-text-font: "Artegra Sans";
 }
 
 [data-md-color-scheme="default"] {

mkdocs.yml

@@ -35,8 +35,7 @@ theme:
   name: material
   logo: logo.svg
   favicon: favicon.png
-  font:
-      text: Artegra Sans
+  font: false
   palette:
     - media: "(prefers-color-scheme: light)"
       scheme: default