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/it.toml

@@ -29,6 +29,10 @@ darkMode   = "Modalità scura"
         warning   = "Avvertenza"
         caution   = "Attenzione"
 
+    [article.codeblock]
+        copy   = "Copia"
+        copied = "Copiato!"
+
 [notFound]
     title    = "Non trovato"
     subtitle = "Questa pagina non esiste."