Disable headings link icons in marky-markdown.

lib/main/build-site.js

@@ -177,7 +177,11 @@ function build() {
     // Uncomment docdown HTML hints.
     .replace(/(<)!--\s*|\s*--(>)/g, '$1$2');
 
-  const $ = cheerio.load(marky(markdown, { 'sanitize': false }));
+  const $ = cheerio.load(marky(markdown, {
+    'enableHeadingLinkIcons': false,
+    'sanitize': false
+  }));
+
   const $header = $('h1').first().remove();
   const version = $header.find('span').first().text().trim().slice(1);