docs(font-stack): drop BlinkMacSystemFont (#34009)

Author: ffoodd

site/content/docs/5.0/content/reboot.md

@@ -37,8 +37,6 @@ $font-family-sans-serif:
   system-ui,
   // Safari for macOS and iOS (San Francisco)
   -apple-system,
-  // Chrome < 56 for macOS (San Francisco)
-  BlinkMacSystemFont,
   // Windows
   "Segoe UI",
   // Android