feat: codeblock improvements (#1328)

* fix: do not show codeblock copy button if clipboard api is not available

related: https://github.com/CaiJimmy/hugo-theme-stack/issues/1309

* fix: remove duplicated codeblock script in main.ts

* feat: add i18n support to codeblock copy button

* feat: add translation strings for codeblock copy button

i18n/vi.toml

@@ -29,6 +29,10 @@ darkMode   = "Chế độ nền tối"
         warning   = "Cảnh báo"
         caution   = "Thận trọng"
 
+    [article.codeblock]
+        copy   = "Sao chép"
+        copied = "Đã sao chép!"
+
 [notFound]
     title    = "Không tìm thấy"
     subtitle = "Trang này không tồn tại"