✨ Feat: add data-open attribute for code block

See http://fixit.lruihao.cn/documentation/content-management/markdown-syntax/extended/#custom-attribute

assets/js/theme.js

@@ -439,7 +439,8 @@ class FixIt {
           $copy.classList.add('copy');
           // remove the leading and trailing whitespace of the code string
           const code = $code.innerText.trim();
-          if (this.config.code.maxShownLines < 0 || code.split('\n').length < this.config.code.maxShownLines + 2) {
+          const forceOpen = $chroma.parentElement.dataset.open ? JSON.parse($chroma.parentElement.dataset.open) : void 0;
+          if (forceOpen ?? (this.config.code.maxShownLines < 0 || code.split('\n').length < this.config.code.maxShownLines + 2)) {
             $chroma.classList.add('open');
           }
           $copy.title = this.config.code.copyTitle;