Remove old scrollbar selectors (#892)

Author: haampie

src/furo/assets/styles/_scaffold.sass

@@ -24,18 +24,9 @@ html
   scroll-behavior: smooth
 
 .sidebar-scroll, .toc-scroll, article[role=main] *
-  // Override Firefox scrollbar style
   scrollbar-width: thin
   scrollbar-color: var(--color-foreground-border) transparent
 
-  // Override Chrome scrollbar styles
-  &::-webkit-scrollbar
-    width: 0.25rem
-    height: 0.25rem
-  &::-webkit-scrollbar-thumb
-    background-color: var(--color-foreground-border)
-    border-radius: 0.125rem
-
 //
 // Overalls
 //