css: remove "Inter" custom font #369

Problem:
Sometimes loading the page takes 5+ seconds, and the browser Network
view shows these files causing the delay:

    https://neovim.io/fonts/inter/inter.css
    https://neovim.io/fonts/inter/Inter-italic.var.woff2?v=3.19
    https://neovim.io/fonts/inter/Inter-roman.var.woff2?v=3.19

Solution:
Drop the use of the custom "Inter" font.
It doesn't look much different than the standard font, AFAICT.

Author: justinmk

css/main.css

@@ -1,9 +1,7 @@
-@import "../fonts/inter/inter.css";
-
 :root {
   --main-breakpoint: 60em;
 
-  --sans-serif-fonts: "Inter", var(--bs-font-sans-serif);
+  --sans-serif-fonts: var(--bs-font-sans-serif);
 
   /* Colors */
   /* Hue is between neovim green and blue for text/background */
@@ -43,7 +41,7 @@
 
 @supports (font-variation-settings: normal) {
   :root {
-    --sans-serif-fonts: "Inter var", var(--bs-font-sans-serif);
+    --sans-serif-fonts: var(--bs-font-sans-serif);
   }
 }