Refine the auto-link selector.

lib/main/build-site.js

@@ -41,12 +41,12 @@ const hlTypes = [
  * @param {Object} $ The Cheerio object.
  */
 function autoLink($) {
-  $('code').each(function() {
+  $('.doc-container code').each(function() {
     const $code = $(this);
     const html = $code.html();
     if (/^_\.\w+$/.test(html)) {
       const id = html.split('.')[1];
-      $code.html(`<a href="#${ id }">_.${ id }</a>`);
+      $code.replaceWith(`<a href="#${ id }"><code>_.${ id }</code></a>`);
     }
   });
 }