Use fontStack token in $body-font

Updating $body-font variable to use --fontStack-sansSerif

Author: lukasoppermann

src/support/variables/typography.scss

@@ -32,7 +32,7 @@ $lh-condensed: 1.25 !default;
 $lh-default: 1.5 !default;
 
 // Font stacks
-$body-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji' !default;
+$body-font: var(--fontStack-sansSerif, -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji') !default;
 
 // Monospace font stack
 // Note: SFMono-Regular needs to come before SF Mono to fix an older version of the font in Chrome