slightly faster attachment of clipboard.js to DOM

assets/js/src/clipboard.js

@@ -14,8 +14,9 @@ if (ClipboardJS.isSupported()) {
 
     // insert button as a sibling to Hugo's code fence
     highlightDiv.insertBefore(button, highlightDiv.firstChild);
+  });
 
-    new ClipboardJS(button, {
+  new ClipboardJS("button.copy-button", {
     text: (trigger) => {
       // actual code element will (should) have class "language-*", even if plaintext
       const fenceElement = trigger.parentElement.querySelector('code[class^="language-"]'); // eslint-disable-line quotes
@@ -34,5 +35,4 @@ if (ClipboardJS.isSupported()) {
     // text needed to be auto-selected to copy, unselect immediately
     e.clearSelection();
   });
-  });
 }