Update useDoc import

See facebook/docusaurus#10316

Author: ptgott

src/theme/DocItem/Layout/index.tsx

@@ -1,7 +1,7 @@
 import React from "react";
 import clsx from "clsx";
 import { useWindowSize } from "@docusaurus/theme-common";
-import { useDoc } from "@docusaurus/theme-common/internal";
+import { useDoc } from "@docusaurus/plugin-content-docs/client";
 import DocItemPaginator from "@theme/DocItem/Paginator";
 import DocVersionBanner from "@theme/DocVersionBanner";
 import DocVersionBadge from "@theme/DocVersionBadge";