feat: copy button for code blocks (#67)

* Add  code copy

* fix: safari copyButton style

* fix: addPreCopyButton up time

* modify: CopyButton style

* fix: Duplicate rendering issue with copy button

src/i18n/i18nKey.ts

@@ -32,6 +32,9 @@ enum I18nKey {
   author = 'author',
   publishedAt = 'publishedAt',
   license = 'license',
+
+  codeCopy = 'copy',
+  codeCopied = 'codeCopied',
 }
 
 export default I18nKey