message: Enable prefetching for all docs menu items.
diff: <ul>
  {#each MENU as menuItem}
  <li>
  - <a href={menuItem.path}>{menuItem.title}</a>
  + <a href={menuItem.path} rel="prefetch">{menuItem.title}</a>
  </li>
  {#if menuItem.subMenu}
  {#each menuItem.subMenu as sub}
  <li>
  - <a href={sub.path}>{sub.title}</a>
  + <a href={sub.path} rel="prefetch">{sub.title}</a>
  </li>
  {/each}
  {/if}
  