docs(site): disable highlightSearchTermsOnTargetPage to keep URLs clean (#12661)

The @easyops-cn/docusaurus-search-local option appends ?_highlight=<term>
query params to links from the search bar. Docusaurus puts the query string
before the #anchor, producing URLs like

    /docs/foo?_highlight=bar#section

which look broken when copy-pasted. Turn the option off — Ctrl+F on the
landing page covers the same use case without polluting shareable links.

website/docusaurus.config.ts

@@ -37,7 +37,9 @@ const config: Config = {
         language: ['en'],
         indexBlog: false,
         docsRouteBasePath: '/',
-        highlightSearchTermsOnTargetPage: true,
+        // Disabled: appends ?_highlight=... to URLs (before the #anchor),
+        // which makes copy/pasted doc links ugly. Ctrl+F on the page is fine.
+        highlightSearchTermsOnTargetPage: false,
       }),
     ],
   ],