Add loading="lazy" to iframe (#383)

Lazy loads the utterances iframe

Author: techboyg5

src/client.ts

@@ -80,7 +80,7 @@ const url = `${utterancesOrigin}/utterances.html`;
 script.insertAdjacentHTML(
   'afterend',
   `<div class="utterances">
-    <iframe class="utterances-frame" title="Comments" scrolling="no" src="${url}?${param(attrs)}"></iframe>
+    <iframe class="utterances-frame" title="Comments" scrolling="no" src="${url}?${param(attrs)}" loading="lazy"></iframe>
   </div>`);
 const container = script.nextElementSibling as HTMLDivElement;
 script.parentElement!.removeChild(script);