Fix scrollbar of SidebarNav to make it tappable (#6586)

Author: tamonmon0417

src/components/Layout/Page.tsx

@@ -129,7 +129,7 @@ export function Page({children, toc, routeTree, meta, section}: PageProps) {
             'grid grid-cols-only-content lg:grid-cols-sidebar-content 2xl:grid-cols-sidebar-content-toc'
         )}>
         {showSidebar && (
-          <div className="lg:-mt-16">
+          <div className="lg:-mt-16 z-10">
             <div className="fixed top-0 py-0 shadow lg:pt-16 lg:sticky start-0 end-0 lg:shadow-none">
               <SidebarNav
                 key={section}