feat(docs): update the docs with customCopyAriaLabel prop

packages/website/docs/components/editors_and_syntax/code.mdx

@@ -93,6 +93,20 @@ export default () => (
 
 ```
 
+You can specify a custom aria label for the Copy button using the `customCopyAriaLabel` prop. It works in conjunction with the `isCopyable` prop.
+
+```tsx
+import React from 'react';
+import { EuiCodeBlock } from '@elastic/eui';
+
+export default () => (
+  <EuiCodeBlock language="html" isCopyable customCopyAriaLabel="Copy the code">
+    {...}
+  </EuiCodeBlock>
+);
+
+```
+
 For long content, you can set an `overflowHeight` which will scroll if the text exceeds that height, and allows users to view the code in fullscreen mode.
 
 ```tsx interactive