feat: remove DOMContentLoaded method

Author: wsafight

src/components/misc/Markdown.astro

@@ -17,10 +17,6 @@ const className = Astro.props.class
   const observer = new MutationObserver(addPreCopyButton);
   observer.observe(document.body, { childList: true, subtree: true });
 
-  if (document.readyState === "loading") {
-    document.addEventListener("DOMContentLoaded", addPreCopyButton);
-  }
-  
   function addPreCopyButton() {
     observer.disconnect();