Only show codeblock copy icon on hover

Fixes #980

resources/assets/js/services/code.js

@@ -113,7 +113,7 @@ function addCopyIcon(cmInstance) {
         copyButton.classList.add('success');
         setTimeout(() => {
             copyButton.classList.remove('success');
-        }, 360);
+        }, 240);
     });
 }