Fix conversion of npm package and source doc links. [ci skip]

lib/main/build-site.js

@@ -175,7 +175,11 @@ function build() {
     // Load markdown.
     .readFileSync(readmePath, 'utf8')
     // Uncomment docdown HTML hints.
-    .replace(/(<)!--\s*|\s*--(>)/g, '$1$2');
+    .replace(/(<)!--\s*|\s*--(>)/g, '$1$2')
+    // Convert source and npm package links to anchors.
+    .replace(/\[source\]\(([^)]+)\) \[npm package\]\(([^)]+)\)/g, (match, href1, href2) =>
+      `<p><a href="${ href1 }">source</a> <a href="${ href2 }">npm package</a></p>`
+    );
 
   const $ = cheerio.load(marky(markdown, {
     'enableHeadingLinkIcons': false,